Existence criteria are investigated here.
Theorem 3.1
The mixed impulsive system (1) admits a unique solution if assertion \(\mathbf{(A)}\) holds and
$$ \max_{1\leq i\leq 3}\{Q_{i}\}< 1. $$
(9)
Proof
Let \(\Omega \subseteq \mathrm{PS}\) and \(\Omega =\{(\mathbb{X},\mathbb{Y},\mathbb{Z})\in \mathrm{PS}:\|( \mathbb{X},\mathbb{Y},\mathbb{Z})\|_{C}\leq \delta _{2}\}\) also \(\delta _{2}=\max \{\delta ,\delta _{1}\}\) and \(\delta ,\delta _{1}\in (0,1)\) provided that
$$ \delta >\max \{N_{1},N_{2},N_{3} \}, $$
and the remaining constants are introduced in the sequel. Now, we define \(\Lambda _{\sigma }:\Omega \rightarrow \Omega \) as
$$ \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr)= \textstyle\begin{cases} E_{\sigma }(A\varsigma ^{\sigma })\omega _{0}+\int _{\varsigma _{0}}^{ \varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } )\mathcal{F} (\varsigma ,\omega ( \varsigma ) )\Delta s \\ \quad {} +\int _{\varsigma _{0}}^{\varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times G (s,\omega (s),\int _{s_{0}}^{s_{f}} \mathcal{F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} \mathcal{F}_{2}(s,u,\omega (u)) \Delta u ) \Delta s, \\ \quad \varsigma \in (\varsigma _{0},\varsigma _{1}], \\ E_{\sigma }(A\varsigma ^{\sigma })\omega _{0}+\int _{\varsigma _{0}}^{ \varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } )\mathcal{F} (\varsigma ,\omega ( \varsigma ) )\Delta s \\ \quad {} +\int _{\varsigma _{0}}^{\varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times G (s,\omega (s),\int _{s_{0}}^{s_{f}} \mathcal{F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} \mathcal{F}_{2}(s,u,\omega (u)) \Delta u ) \Delta s \\ \quad {} +\sum_{j=1}^{i} (\Xi _{j}(\omega (\varsigma ^{-}_{j}))+\Phi _{j} (\varsigma ^{-}_{j},\omega (\varsigma ^{-}_{j})) ),\quad \varsigma \in (\varsigma _{i},\varsigma _{i+1}], i = 1,\dots , m. \end{cases} $$
(10)
Assume that
$$ \bigl\Vert \mathcal{F}(s,\omega ) \bigr\Vert \leq \bigl\Vert \mathcal{F}(s,\omega )-\mathcal{F}(s,0) \bigr\Vert + \bigl\Vert \mathcal{F}(s,0) \bigr\Vert \leq L_{\mathcal{F}} \Vert \omega \Vert +M_{\mathcal{F}} $$
and
$$\begin{aligned} \bigl\Vert G(\varsigma ,\mathbb{X},\mathbb{Y},\mathbb{Z}) \bigr\Vert &\leq \bigl\Vert G( \varsigma ,\mathbb{X},\mathbb{Y},\mathbb{Z})-G(\varsigma ,0,0,0) \bigr\Vert + \bigl\Vert G( \varsigma ,0,0,0) \bigr\Vert \\ &\leq L_{\hbar _{1}} \Vert \mathbb{X} \Vert +L_{\hbar _{2}} \Vert \mathbb{Y} \Vert +L_{ \hbar _{3}} \Vert \mathbb{Z} \Vert +M_{G}, \end{aligned}$$
where \(M_{\mathcal{F}}=\sup_{\varsigma \in \mathbb{T}}\|\mathcal{F}(s,0)\|\), \(M_{G}=\sup_{\varsigma \in \mathbb{T}}\|G(\varsigma ,0,0,0)\|\), and \(\widehat{M}_{G}=M_{\mathcal{F}}+M_{G}\). In addition, \(\mathbb{X}=\omega (s)\), \(\mathbb{Y}=\int _{s_{0}}^{s_{f}} \mathcal{F}_{1}(s,u, \omega (u))\Delta u\), and \(\mathbb{Z}=\int _{s_{0}}^{s_{f}} \mathcal{F}_{2}(s,u, \omega (u))\Delta u\).
Now, we prove that \(\Lambda _{\sigma }:\Omega \rightarrow \Omega \) is a self-mapping.
For \(\varsigma \in (\varsigma _{i},\varsigma _{i+1}]\), \(i = 1,\dots , m\), one has
$$\begin{aligned} \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq& \sum_{j=1}^{i} \bigl\Vert \Xi _{j}\bigl(\omega \bigl(\varsigma ^{-}_{j} \bigr)\bigr) \bigr\Vert +\sum_{j=1}^{i} \bigl\Vert \Phi _{j} \bigl(\varsigma ^{-}_{j}, \omega \bigl(\varsigma ^{-}_{j}\bigr)\bigr) \bigr\Vert + \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{\sigma }\bigr)\omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl\Vert \biggl(\mathcal{F} \bigl(s,\omega (s)\bigr) \\ &{} +G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr) \biggr\Vert \Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \sum_{j=1}^{i}{L}_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \bigl\Vert E_{ \sigma }\bigl(A\varsigma ^{\sigma }\bigr) \omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl( \bigl\Vert \mathcal{F}\bigl(s,\omega (s)\bigr) \bigr\Vert \\ &{} + \biggl\Vert G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr\Vert +\widehat{M}_{G} \biggr)\Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \sum_{j=1}^{i}{L}_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \bigl\Vert E_{ \sigma }\bigl(A\varsigma ^{\sigma }\bigr) \omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl({L}_{ \mathcal{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{\hbar _{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &{} +{L}_{\hbar _{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \mathcal{F}_{1}\bigl(s,u, \omega (u)\bigr) \bigr\Vert \Delta u+{L}_{\hbar _{3}} \int _{s_{0}}^{s_{f}} \bigl\Vert \mathcal{F}_{2}\bigl(s,u,\omega (u)\bigr) \bigr\Vert \Delta u+ \widehat{M}_{G} \biggr)\Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \sum_{j=1}^{i}{L}_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \bigl\Vert E_{ \sigma }\bigl(A\varsigma ^{\sigma }\bigr) \omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl({L}_{ \mathcal{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{{G}_{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &{} +{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u) \bigr\Vert \Delta u+{L}_{{G}_{3}}{L}_{ \mathcal{\mathcal{F}}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u) \bigr\Vert \Delta u+\widehat{M}_{G} \biggr)\Delta s \\ =&\sum_{j=1}^{i}{L}_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \sum_{j=1}^{i}{L}_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \bigl\Vert E_{ \sigma }\bigl(A\varsigma ^{\sigma }\bigr) \omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \bigl({L}_{ \mathcal{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{{G}_{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &{} +{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}})+{L}_{{G}_{3}}{L}_{ \mathcal{\mathcal{F}}_{2}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}})+ \widehat{M}_{G} \bigr)\Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert +\sum _{j=1}^{i}{L}_{\Phi }\sup _{ \varsigma \in \mathbb{T}} \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert + \sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{\sigma }\bigr) \omega _{0} \bigr\Vert \\ &{} + \int _{\varsigma _{0}}^{\varsigma _{f}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma ,\sigma } \bigl(A(\varsigma -s)^{\sigma } \bigr) \bigr\Vert \Bigl({L}_{\mathcal{F}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s) \bigr\Vert \\ &{} +{L}_{{G}_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}}) \\ &{}+{L}_{{G}_{3}}{L}_{ \mathcal{\mathcal{F}}_{2}} \sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}})+\widehat{M}_{G} \Bigr) \Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \Vert \omega \Vert _{\infty }+\sum_{j=1}^{i}{L}_{ \Phi } \Vert \omega \Vert _{\infty }+a_{1}+ \int _{\varsigma _{0}}^{\varsigma _{f}}a_{3}a_{2} \bigl({L}_{\mathcal{F}} \Vert \omega \Vert _{\infty }+{L}_{{G}_{1}} \Vert \omega \Vert _{ \infty } \\ &{} +{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}})+{L}_{{G}_{3}}{L}_{ \mathcal{\mathcal{F}}_{2}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}})+ \widehat{M}_{G} \bigr)\Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \delta +\sum_{j=1}^{i}{L}_{\Phi } \delta +a_{1} +a_{3} \bigl(\delta a_{2}{L}_{\mathcal{F}}+ \delta a_{2}{L}_{{G}}+ \delta a_{2}{L}_{{G}}{L}_{\mathcal{\mathcal{F}}_{1}}({s_{f}}-{s_{0}}) \\ &{} +\delta a_{2}{L}_{{G}}{L}_{\mathcal{\mathcal{F}}_{2}}({s_{f}}-{s_{0}})+ \widehat{M}_{G} \bigr)\times \int _{\varsigma _{0}}^{\varsigma _{f}} \Delta s \\ \leq& \sum_{j=1}^{i}{L}_{\Xi } \delta +\sum_{j=1}^{i}{L}_{\Phi } \delta +a_{1} +\delta a_{3} \bigl(a_{2}{L}_{\mathcal{F}}+ a_{2}{L}_{{G}_{1}}+ a_{2}{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}}({s_{f}}-{s_{0}}) \\ &{} + a_{2}{L}_{{G}_{3}}{L}_{\mathcal{\mathcal{F}}_{2}}({s_{f}}-{s_{0}})+ \widehat{M}_{G} \bigr) (\varsigma -\varsigma _{f}). \end{aligned}$$
So
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq N_{1}+\delta Q_{1} \leq \delta +\delta Q_{1} = \delta _{1}, $$
where \(\delta _{1}=\delta +\delta Q_{1}\). Hence
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq \delta _{2}. $$
(11)
Therefore, from (11), \(\Lambda (\Omega ) \subseteq \Omega \). Also, for \(\varsigma \in (\varsigma _{i},\varsigma _{i+1}]\), \(i = 1,\dots , m\), with \(\omega _{0}=\widehat{\omega }_{0}\), one has
$$\begin{aligned} & \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Lambda _{\sigma } \bigl(\widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \\ &\quad \leq \sum_{j=1}^{i} \bigl\Vert \Xi _{j}\bigl(\omega \bigl(\varsigma ^{-}_{j} \bigr)\bigr)-\Xi _{j}\bigl(\widehat{{\omega }}\bigl( \varsigma ^{-}_{j}\bigr)\bigr) \bigr\Vert \\ &\qquad {}+\sum_{j=1}^{i} \bigl\Vert \Phi _{j} \bigl(\varsigma ^{-}_{j},\omega \bigl( \varsigma ^{-}_{j}\bigr)\bigr)-\Phi _{j} \bigl(\varsigma ^{-}_{j},\widehat{{\omega }}\bigl( \varsigma ^{-}_{j}\bigr)\bigr) \bigr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl\Vert \biggl(\mathcal{F} \bigl(s,\omega (s)\bigr) \\ &\qquad {}+G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr) \\ &\qquad {}- \biggl(\mathcal{F}\bigl(s,\widehat{\omega }(s)\bigr) \\ &\qquad {}+G \biggl(s,\widehat{\omega }(s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u \biggr) \biggr) \biggr\Vert \Delta s \\ &\quad \leq \sum_{j=1}^{i}L_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert +\sum_{j=1}^{i}L_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl( \bigl\Vert \mathcal{F} \bigl(s,\omega (s)\bigr)-\mathcal{F}\bigl(s,\widehat{\omega }(s)\bigr) \bigr\Vert \\ &\qquad {}+ \biggl\Vert G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \\ &\qquad {}-G \biggl(s,\widehat{\omega }(s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u \biggr) \biggr\Vert \biggr)\Delta s \\ &\quad \leq \sum_{j=1}^{i}L_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert +\sum_{j=1}^{i}L_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl(L_{F} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{\mathcal{G}_{1}} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert +L_{ \mathcal{G}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \mathcal{F}_{1}\bigl(s,u, \omega (u)\bigr)-\mathcal{F}_{1} \bigl(s,u,\widehat{\omega }(u)\bigr) \bigr\Vert \Delta u \\ &\qquad {}+ L_{{G}_{3}} \int _{s_{0}}^{s_{f}} \bigl\Vert \mathcal{F}_{2}\bigl(s,u,\omega (u)\bigr)- \mathcal{F}_{2} \bigl(s,u,\widehat{\omega }(u)\bigr) \bigr\Vert \Delta u \biggr)\Delta s \\ &\quad \leq \sum_{j=1}^{i}L_{\Xi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert +\sum_{j=1}^{i}L_{\Phi } \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)- \widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl(L_{ \mathcal{F}} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{{G}_{1}} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert +L_{{G}_{2}}L_{{ \mathcal{F}_{1}}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u)- \widehat{\omega }(u) \bigr\Vert \Delta u \\ &\qquad {}+ L_{{G}_{3}}L_{{\mathcal{F}}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u)- \widehat{\omega }(u) \bigr\Vert \Delta u \biggr)\Delta s \\ &\quad \leq \sum_{j=1}^{i}L_{\Xi } \sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)-\widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert +\sum _{j=1}^{i}L_{\Phi }\sup _{\varsigma \in \mathbb{T}} \bigl\Vert \omega \bigl(\varsigma ^{-}_{j}\bigr)-\widehat{{\omega }}\bigl(\varsigma ^{-}_{j}\bigr) \bigr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma ,\sigma } \bigl(A(\varsigma -s)^{\sigma } \bigr) \bigr\Vert \Bigl(L_{\mathcal{F}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{{G}_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert +L_{{G}_{2}}L_{{\mathcal{F}_{1}}}\sup _{ \varsigma \in \mathbb{T}} \bigl\Vert \omega (u)-\widehat{\omega }(u) \bigr\Vert ({s_{f}}-{s_{0}}) \\ &\qquad {}+ L_{{G}_{3}}L_{{\mathcal{F}}_{2}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u)-\widehat{\omega }(u) \bigr\Vert ({s_{f}}-{s_{0}}) \Bigr) \Delta s \\ &\quad =\sum_{j=1}^{i}L_{\Xi } \Vert \omega -\widehat{{\omega }} \Vert _{ \infty }+\sum _{j=1}^{i}L_{\Phi } \Vert \omega - \widehat{{\omega }} \Vert _{ \infty } \\ &\qquad {}+a_{3}a_{2} \bigl(L_{\mathcal{F}} \Vert \omega - \widehat{\omega } \Vert _{ \infty }+L_{{G}_{1}} \Vert \omega - \widehat{\omega } \Vert _{\infty }+L_{{G}_{2}}L_{{ \mathcal{F}_{1}}} \Vert \omega -\widehat{\omega } \Vert _{\infty }({s_{f}}-{s_{0}}) \\ &\qquad {}+ L_{{G}_{3}}L_{{\mathcal{F}}_{2}} \Vert \omega -\widehat{\omega } \Vert _{\infty }({s_{f}}-{s_{0}}) \bigr) \int _{\varsigma _{0}}^{ \varsigma _{f}}\Delta s \\ &\quad \leq \Biggl[\sum_{j=1}^{i}L_{\Xi }+ \sum_{j=1}^{i}L_{\Phi } \\ &\qquad {}+a_{3} \bigl(a_{2}L_{\mathcal{F}}+a_{2}L_{{G}_{1}}+a_{2}L_{{G}_{2}}L_{{ \mathcal{F}_{1}}}({s_{f}}-{s_{0}})+ a_{2}L_{{G}_{3}}L_{{\mathcal{F}}_{2}}({s_{f}}-{s_{0}}) \bigr) (\varsigma -\varsigma _{f}) \Biggr] \\ &\qquad {}\times \Vert \omega -\widehat{\omega } \Vert _{\infty }. \end{aligned}$$
It implies
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Lambda _{\sigma } \bigl(\widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \leq (N_{2}+ Q_{2} ) \Vert \omega -\widehat{\omega } \Vert _{\infty }= Q_{3} \Vert \omega - \widehat{\omega } \Vert _{\infty }. $$
Hence
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Lambda _{\sigma } \bigl(\widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \leq Q_{3} \Vert \omega - \widehat{\omega } \Vert _{\infty }\quad (Q_{3}< 1). $$
(12)
Therefore, from inequality (12) and (9), the operator \(\Lambda _{\sigma }\) is strictly contractive. Consequently, the mixed impulsive system (1) admits a unique solution via the Banach principle. □
Now, regarding the mixed impulsive system (2), we have the following result.
Theorem 3.2
The mixed impulsive system (2) involves a unique solution if assertion \(\mathbf{(A)}\) holds and
$$ \max_{1\leq i\leq 3}\bigl\{ Q^{*}_{i} \bigr\} < 1. $$
(13)
Proof
Let \(\Omega \subseteq \mathrm{PS}\) and \(\Omega =\{(\mathbb{X},\mathbb{Y},\mathbb{Z})\in \mathrm{PS}:\|( \mathbb{X},\mathbb{Y},\mathbb{Z})\|_{C}\leq \delta _{2}\}\), also \(\delta _{2}=\max \{\delta ,\delta _{1}\}\) and \(\delta ,\delta _{1}\in (0,1)\) provided that
$$ \delta >\max \{N_{1},N_{2},N_{3} \}. $$
Now, we define \(\Psi _{\sigma }:\Omega \rightarrow \Omega \) as
$$ \Psi _{\sigma } \bigl(\omega (\varsigma ) \bigr)= \textstyle\begin{cases} E_{\sigma }(A\varsigma ^{\sigma })\omega _{0} +\int _{\varsigma _{0}}^{ \varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } ){F} (\varsigma ,\omega (\varsigma ) )\Delta s \\ \quad {} +\int _{\varsigma _{0}}^{\varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times \mathcal{G} (s,\omega (s),\int _{s_{0}}^{s_{f}} {F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} {F}_{2}(s,u,\omega (u)) \Delta u ) \Delta s, \\ \quad \varsigma \in (\varsigma _{i}, s_{i}]\cap \mathbb{{T}}, i = 1, \dots , m, \\ E_{\sigma }(A\varsigma ^{\sigma })\omega _{0} +\int _{\varsigma _{0}}^{ \varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } ){F} (\varsigma ,\omega (\varsigma ) )\Delta s \\ \quad {} +\int _{\varsigma _{0}}^{\varsigma _{f}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times \mathcal{G} (s,\omega (s),\int _{s_{0}}^{s_{f}} {F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} {F}_{2}(s,u,\omega (u)) \Delta u ) \Delta s \\ \quad {} +\frac{1}{\Gamma (\sigma )}\int _{\varsigma _{i}}^{s_{i}}(\varsigma -s)^{ \sigma -1}\hbar _{i}(s,\omega (s))\Delta s,\quad \varsigma \in (s_{i}, \varsigma _{i+1}]\cap \mathbb{{T}}, i = 1,\dots , m. \end{cases} $$
(14)
Also, note that
$$ \bigl\Vert {F}(s,\omega ) \bigr\Vert \leq \bigl\Vert {F}(s,\omega )-{F}(s,0) \bigr\Vert + \bigl\Vert {F}(s,0) \bigr\Vert \leq L_{{F}} \Vert \omega \Vert +M_{{F}} $$
and
$$\begin{aligned} \bigl\Vert \mathcal{G}(\varsigma ,\mathbb{X},\mathbb{Y},\mathbb{Z}) \bigr\Vert \leq & \bigl\Vert \mathcal{G}(\varsigma ,\mathbb{X},\mathbb{Y}, \mathbb{Z})-\mathcal{G}( \varsigma ,0,0,0) \bigr\Vert + \bigl\Vert \mathcal{G}(\varsigma ,0,0,0) \bigr\Vert \\ \leq &L_{\mathcal{G}_{1}} \Vert \mathbb{X} \Vert +L_{\mathcal{G}_{2}} \Vert \mathbb{Y} \Vert +L_{\mathcal{G}_{3}} \Vert \mathbb{Z} \Vert +M_{\mathcal{G}}, \end{aligned}$$
where \(M_{{F}}=\sup_{\varsigma \in \mathbb{T}}\|{F}(s,0)\|\), \(M_{ \mathcal{G}}=\sup_{\varsigma \in \mathbb{T}}\|\mathcal{G}(\varsigma ,0,0,0) \|\), and \(\widehat{M}_{\mathcal{G}}=M_{{F}}+M_{\mathcal{G}}\). In addition, \(\mathbb{X}=\omega (s)\), \(\mathbb{Y}=\int _{s_{0}}^{s_{f}} {F}_{1}(s,u,\omega (u)) \Delta u\), and \(\mathbb{Z}=\int _{s_{0}}^{s_{f}} {F}_{2}(s,u,\omega (u)) \Delta u\).
Now, we prove that \(\Psi _{\sigma }:\Omega \rightarrow \Omega \) is a self-mapping.
For \(\varsigma \in (s_{i}, \varsigma _{i+1}]\cap \mathbb{{T}}\), \(i = 1, \dots , m\), one has
$$\begin{aligned} \bigl\Vert \Psi _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert &\leq \biggl\Vert \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}}(\varsigma -s)^{ \sigma -1} \hbar _{i}\bigl(s,\omega (s)\bigr)\Delta s \biggr\Vert + \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{ \sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl\Vert \biggl({F}\bigl(s, \omega (s)\bigr) \\ &\quad {}+\mathcal{G} \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} {F}_{2}\bigl(s,u, \omega (u)\bigr) \Delta u \biggr) \biggr) \biggr\Vert \Delta s \\ &\leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert \hbar _{i}\bigl(s, \omega (s)\bigr) \bigr\Vert \Delta s+ \bigl\Vert E_{\sigma }\bigl(A \varsigma ^{\sigma }\bigr) \bigr\Vert \Vert \omega _{0} \Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl( \bigl\Vert {F} \bigl(s,\omega (s)\bigr) \bigr\Vert \\ &\quad {}+ \biggl\Vert \mathcal{G} \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} {F}_{2}\bigl(s,u, \omega (u)\bigr) \Delta u \biggr) \biggr\Vert +\widehat{M}_{\mathcal{G}} \biggr)\Delta s \\ &\leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \bigl(\omega (s)\bigr) \bigr\Vert \Delta s+ \bigl\Vert E_{ \sigma }\bigl(A\varsigma ^{\sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl({L}_{{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{\mathcal{G}_{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &\quad {}+{L}_{\mathcal{G}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert {F}_{1} \bigl(s,u, \omega (u)\bigr) \bigr\Vert \Delta u+{L}_{\mathcal{G}_{3}} \int _{s_{0}}^{s_{f}} \bigl\Vert {F}_{2} \bigl(s,u,\omega (u)\bigr) \bigr\Vert \Delta u+\widehat{M}_{\mathcal{G}} \biggr)\Delta s \\ &\leq \frac{1}{\Gamma (\sigma )} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \bigl(\omega (s)\bigr) \bigr\Vert ({s_{i}}-{\varsigma _{i}})+ \bigl\Vert E_{\sigma }\bigl(A \varsigma ^{\sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl({L}_{{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{{\mathcal{G}}_{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &\quad {}+{L}_{{\mathcal{G}}_{2}}{L}_{{F}_{1}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u) \bigr\Vert \Delta u+{L}_{{\mathcal{G}}_{3}}{L}_{{F}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u) \bigr\Vert \Delta u+\widehat{M}_{\mathcal{G}} \biggr)\Delta s \\ &=\frac{1}{\Gamma (\sigma )} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \bigl( \omega (s)\bigr) \bigr\Vert ({s_{i}}-{\varsigma _{i}})+ \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{ \sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \bigl({L}_{{F}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{{\mathcal{G}}_{1}} \bigl\Vert \omega (s) \bigr\Vert \\ &\quad {}+{L}_{\mathcal{G}_{2}}{L}_{{F}_{1}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}})+{L}_{ \mathcal{G}_{3}}{L}_{F_{2}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}}) + \widehat{M}_{\mathcal{G}} \bigr)\Delta s \\ &\leq \frac{1}{\Gamma (\sigma )}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert L_{g}\sup _{\varsigma \in \mathbb{T}} \bigl\Vert \bigl(\omega (s)\bigr) \bigr\Vert ({s_{i}}-{\varsigma _{i}})+\sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{\sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma ,\sigma } \bigl(A(\varsigma -s)^{\sigma } \bigr) \bigr\Vert \Bigl({L}_{F}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s) \bigr\Vert \\ &\quad {}+{L}_{ \mathcal{G}_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s) \bigr\Vert +{L}_{\mathcal{G}_{2}}{L}_{F_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}}) \\ &\quad {}+{L}_{\mathcal{G}_{3}}{L}_{F_{2}} \sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u) \bigr\Vert ({s_{f}}-{s_{0}})+ \widehat{M}_{\mathcal{G}} \Bigr) \Delta s \\ &\leq \frac{1}{\Gamma (\sigma )}a_{3}L_{g} \Vert \omega \Vert _{\infty }({s_{i}}-{ \varsigma _{i}})+a_{1}+ \int _{\varsigma _{0}}^{\varsigma _{f}}a_{3}a_{2} \bigl(L_{F} \Vert \omega \Vert _{\infty } +{L}_{\mathcal{G}_{1}} \Vert \omega \Vert _{ \infty } \\ &\quad {}+{L}_{\mathcal{G}_{2}}{L}_{F_{1}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}})+{L}_{ \mathcal{G}_{3}}{L}_{F_{2}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}})+ \widehat{M}_{\mathcal{G}} \bigr)\Delta s \\ &\leq \frac{1}{\Gamma (\sigma )}a_{3}L_{g}\delta ({s_{i}}-{\varsigma _{i}})+a_{1}+a_{3} \bigl(\delta a_{2}{L}_{F}+\delta a_{2}{L}_{\mathcal{G}}+ \delta a_{2}{L}_{ \mathcal{G}}{L}_{F_{1}}({s_{f}}-{s_{0}}) \\ &\quad {}+\delta a_{2}{L}_{\mathcal{G}}{L}_{F_{2}}({s_{f}}-{s_{0}})+ \widehat{M}_{\mathcal{G}} \bigr)\times \int _{\varsigma _{0}}^{ \varsigma _{f}}\Delta s \\ &\leq \frac{1}{\Gamma (\sigma )}a_{3}L_{g}\delta ({s_{i}}-{\varsigma _{i}})+a_{1}+ \delta a_{3} \bigl(a_{2}{L}_{F}+ a_{2}{L}_{\mathcal{G}_{1}}+ a_{2}{L}_{ \mathcal{G}_{2}}{L}_{F_{1}}({s_{f}}-{s_{0}}) \\ &\quad {}+ a_{2}{L}_{\mathcal{G}_{3}}{L}_{F_{2}}({s_{f}}-{s_{0}})+ \widehat{M}_{ \mathcal{G}} \bigr) (\varsigma -\varsigma _{f}). \end{aligned}$$
Thus
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq N_{3}+\delta Q^{*}_{1} \leq \delta +\delta Q^{*}_{1}=\delta _{1}, $$
where \(\delta _{1}=\delta +\delta Q^{*}_{1}\). Hence
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq \delta _{2}. $$
(15)
Therefore, from (15), \(\Psi _{\sigma }(\Omega )\subseteq \Omega \). Also, for \(\varsigma \in (s_{i}, \varsigma _{i+1}]\cap \mathbb{{T}}\), \(i = 1, \dots , m\), with \(\omega _{0}=\widehat{\omega }_{0}\), we have
$$\begin{aligned} &\bigl\Vert \Psi _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Psi _{\sigma } \bigl( \widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \\ &\quad \leq \biggl\Vert \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}}(\varsigma -s)^{ \sigma -1} \bigl(\hbar _{i}\bigl(s,\omega (s)\bigr)-\hbar _{i} \bigl(s,\widehat{\omega }(s)\bigr) \bigr)\Delta s \biggr\Vert \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl\Vert \biggl({F}\bigl(s, \omega (s)\bigr) \\ &\qquad {}+\mathcal{G} \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} {F}_{2}\bigl(s,u, \omega (u)\bigr) \Delta u \biggr) \biggr) \\ &\qquad {}- \biggl({F}\bigl(s,\widehat{\omega }(s)\bigr) \\ &\qquad {}+\mathcal{G} \biggl(s,\widehat{\omega }(s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} {F}_{2}\bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u \biggr) \biggr) \biggr\Vert \Delta s \\ &\quad \leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert \hbar _{i}\bigl(s, \omega (s)\bigr)-\hbar _{i}\bigl(s, \widehat{\omega }(s)\bigr) \bigr\Vert \Delta s \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl( \bigl\Vert F\bigl(s, \omega (s)\bigr)-F\bigl(s,\widehat{\omega }(s)\bigr) \bigr\Vert \\ &\qquad {}+ \biggl\Vert \mathcal{G} \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} {F}_{2}\bigl(s,u, \omega (u)\bigr) \Delta u \biggr) \\ &\qquad {}-\mathcal{G} \biggl(s,\widehat{\omega }(s), \int _{s_{0}}^{s_{f}} {F}_{1}\bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} F_{2}\bigl(s,u, \widehat{\omega }(u)\bigr)\Delta u \biggr) \biggr\Vert \biggr)\Delta s \\ &\quad \leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert \Delta s \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl(L_{F} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{\mathcal{G}_{1}} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert +L_{ \mathcal{G}_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert F_{1} \bigl(s,u,\omega (u)\bigr)-F_{1}\bigl(s,u, \widehat{\omega }(u)\bigr) \bigr\Vert \Delta u \\ &\qquad {}+ L_{\mathcal{G}_{3}} \int _{s_{0}}^{s_{f}} \bigl\Vert F_{2} \bigl(s,u,\omega (u)\bigr)-F_{2}\bigl(s,u, \widehat{\omega }(u)\bigr) \bigr\Vert \Delta u \biggr)\Delta s \\ &\quad \leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}} \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert \Delta s \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl(L_{F} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{\mathcal{G}_{1}} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert +L_{ \mathcal{G}_{2}}L_{F_{1}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u)- \widehat{\omega }(u) \bigr\Vert \Delta u \\ &\qquad {}+ L_{\mathcal{G}_{3}}L_{F_{2}} \int _{s_{0}}^{s_{f}} \bigl\Vert \omega (u)- \widehat{\omega }(u) \bigr\Vert \Delta u \biggr)\Delta s \\ &\quad \leq \frac{1}{\Gamma (\sigma )} \int _{\varsigma _{i}}^{s_{i}}\sup_{ \varsigma \in \mathbb{T}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert L_{g} \bigl\Vert \omega (s)-\widehat{\omega }(s) \bigr\Vert \Delta s \\ &\qquad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \sup_{\varsigma \in \mathbb{T}} \bigl\Vert E_{\sigma ,\sigma } \bigl(A(\varsigma -s)^{\sigma } \bigr) \bigr\Vert \Bigl(L_{F}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert \\ &\qquad {}+L_{\mathcal{G}_{1}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (s)- \widehat{\omega }(s) \bigr\Vert +L_{\mathcal{G}_{2}}L_{F_{1}} \sup _{ \varsigma \in \mathbb{T}} \bigl\Vert \omega (u)-\widehat{\omega }(u) \bigr\Vert ({s_{f}}-{s_{0}}) \\ &\qquad {}+ L_{\mathcal{G}_{3}}L_{F_{2}}\sup_{\varsigma \in \mathbb{T}} \bigl\Vert \omega (u)-\widehat{\omega }(u) \bigr\Vert ({s_{f}}-{s_{0}}) \Bigr)\Delta s \\ &\quad =\frac{1}{\Gamma (\sigma )}a_{3}L_{g} \Vert \omega - \widehat{\omega } \Vert _{\infty } \int _{\varsigma _{0}}^{\varsigma _{f}}\Delta s \\ &\qquad {}+a_{3}a_{2} \bigl(L_{F} \Vert \omega - \widehat{\omega } \Vert _{\infty }+L_{{ \mathcal{G}}_{1}} \Vert \omega - \widehat{\omega } \Vert _{\infty } +L_{{ \mathcal{G}}_{2}}L_{{{F}_{1}}} \Vert \omega -\widehat{\omega } \Vert _{ \infty }({s_{f}}-{s_{0}}) \\ &\qquad {}+ L_{{\mathcal{G}}_{3}}L_{{{F}}_{2}} \Vert \omega -\widehat{\omega } \Vert _{\infty }({s_{f}}-{s_{0}}) \bigr) \int _{\varsigma _{0}}^{ \varsigma _{f}}\Delta s \\ &\quad \leq \biggl[\frac{1}{\Gamma (\sigma )}a_{3}L_{g}({ \varsigma _{f}}-{ \varsigma _{0}})+a_{3} \bigl(a_{2}L_{{F}}+a_{2}L_{{G}_{1}}+a_{2}L_{{ \mathcal{G}}_{2}}L_{{{F}_{1}}}({s_{f}}-{s_{0}}) \\ &\qquad {}+ a_{2}L_{{\mathcal{G}}_{3}}L_{{\mathcal{F}}_{2}}({s_{f}}-{s_{0}}) \bigr) (\varsigma -\varsigma _{f}) \biggr] \Vert \omega - \widehat{\omega } \Vert _{\infty }. \end{aligned}$$
It implies
$$ \bigl\Vert \Psi _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Psi _{\sigma } \bigl( \widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \leq (N_{4}+ Q_{2} ) \Vert \omega -\widehat{\omega } \Vert _{\infty }\leq Q^{*}_{3} \Vert \omega - \widehat{\omega } \Vert _{\infty }. $$
Hence
$$ \bigl\Vert \Psi _{\sigma } \bigl(\omega (\varsigma ) \bigr)-\Psi _{\sigma } \bigl( \widehat{\omega }(\varsigma ) \bigr) \bigr\Vert \leq Q^{*}_{3} \Vert \omega - \widehat{\omega } \Vert _{\infty }. $$
(16)
Therefore, from (16) and (13), the operator \(\Psi _{\sigma }\) is strictly contractive. Consequently, the second impulsive system (2) admits a unique solution via the Banach principle. □
Next, for both mixed impulsive systems (1) and (2), we investigate the existence of at least one solution via the weaker condition \((\mathbf{B})\) and the Leray–Schauder alternative fixed point method.
Theorem 3.3
The mixed impulsive system (1) has at least one solution provided assumption \((\mathbf{B})\) holds and \(\mathcal{K}>0\) exists so that
$$ a_{1}+Q_{3}\mathcal{K}< \mathcal{K}. $$
(17)
Proof
Firstly, we prove that \(\Lambda _{\sigma }\) defined by (10) is a completely continuous operator. We see that the continuity of the mappings Ξ, Φ, \(\mathcal{F}\), and G provides that \(\Lambda _{\sigma }\) is a continuous operator. Also, assume that \(\Omega _{1}{\subseteq }PS\) along with the fact that the operators Ξ, Φ, \(\mathcal{F}\), and G are bounded. Then there exist \(L_{1}\), \(L_{2}\), \(M_{1}\), and \(M_{2}\) (positive constants) such that \(\sum_{j=1}^{i}\Xi _{j}(\omega )\leq L_{1}\), \(\sum_{j=1}^{i}\Phi _{j}(\omega )\leq L_{2}\), \(\mathcal{F} (\varsigma , \omega (\varsigma ) )\leq M_{1}\), and \(G(\varsigma ,\mathbb{X},\mathbb{Y},\mathbb{Z})\leq M_{2}\), where \(p=\omega (s)\),
$$ q= \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u,\omega (u)\bigr) \Delta u, $$
and
$$ r= \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u. $$
Note that we take \(\mathcal{L}=L_{4}+L_{5}+a_{1}\), \(\mathcal{M}=M_{1}+M_{2}\), \(\|(\varsigma -s)^{\sigma -1}\|\leq \mathcal{L}_{1}\), and \(\mathcal{L}+\mathcal{L}_{1}a_{2}\mathcal{M}({\varsigma _{f}}-{ \varsigma _{0}})=\mathfrak{G}\).
Then, for any \(\omega \in \Omega _{1}\) and \(\varsigma \in (\varsigma _{i},\varsigma _{i+1}]\), \(i = 1,\dots , m\), we have
$$\begin{aligned} \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert &\leq \sum_{j=1}^{i} \bigl\Vert \Xi _{j}\bigl(\omega \bigl(\varsigma ^{-}_{j} \bigr)\bigr) \bigr\Vert +\sum_{j=1}^{i} \bigl\Vert \Phi _{j} \bigl(\varsigma ^{-}_{j}, \omega \bigl(\varsigma ^{-}_{j}\bigr)\bigr) \bigr\Vert + \bigl\Vert E_{\sigma }\bigl(A\varsigma ^{\sigma }\bigr)\omega _{0} \bigr\Vert \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f}} \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert \bigl\Vert E_{\sigma ,\sigma } \bigl(A( \varsigma -s)^{\sigma } \bigr) \bigr\Vert \biggl\Vert \biggl(\mathcal{F} \bigl(s,\omega (s)\bigr) \\ &\quad {}+G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr) \biggr\Vert \Delta s \\ &\leq L_{4}+L_{5}+a_{1}+ \mathcal{L}_{1}a_{2}(M_{1}+M_{2}) \int _{ \varsigma _{0}}^{\varsigma _{f}}\Delta s \\ &= \mathcal{L}+\mathcal{L}_{1}a_{2}\mathcal{M}({ \varsigma _{f}}-{ \varsigma _{0}}). \end{aligned}$$
It implies
$$ \bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr) \bigr\Vert \leq \mathfrak{G}. $$
(18)
Thus, from (18), we conclude that Λ is uniformly bounded.
Now, we prove that \(\Lambda _{\sigma }\) is completely continuous. For this, we discuss the following possibilities.
Case 1: Assume that all points on \(\mathbb{T}\) are isolated, i.e., time scales consist of discrete points. Using Theorem 2.2, \(\Lambda _{\sigma }\) becomes
$$ \Lambda _{\sigma } \bigl(\omega (\varsigma ) \bigr)= \textstyle\begin{cases} E_{\sigma }(A\varsigma ^{\sigma })\omega _{0}+\sum_{\varsigma \in \mathbb{T}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } )\mathcal{F} (\varsigma ,\omega ( \varsigma ) )\Delta s \\ \quad {} +\sum_{\varsigma \in \mathbb{T}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times G (s,\omega (s),\int _{s_{0}}^{s_{f}} \mathcal{F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} \mathcal{F}_{2}(s,u,\omega (u)) \Delta u ), \\ \quad \varsigma \in (\varsigma _{0},\varsigma _{1}], \\ E_{\sigma }(A\varsigma ^{\sigma })\omega _{0}+\sum_{\varsigma \in \mathbb{T}}(\varsigma -s)^{\sigma -1}E_{\sigma ,\sigma } (A( \varsigma -s)^{\sigma } )\mathcal{F} (\varsigma ,\omega ( \varsigma ) )\Delta s \\ \quad {} +\sum_{\varsigma \in \mathbb{T}}(\varsigma -s)^{\sigma -1}E_{ \sigma ,\sigma } (A(\varsigma -s)^{\sigma } ) \\ \quad {} \times G (s,\omega (s),\int _{s_{0}}^{s_{f}} \mathcal{F}_{1}(s,u, \omega (u))\Delta u,\int _{s_{0}}^{s_{f}} \mathcal{F}_{2}(s,u,\omega (u)) \Delta u ) \Delta s \\ \quad {} +\sum_{j=1}^{i} (\Xi _{j}(\omega (\varsigma ^{-}_{j}))+\Phi _{j} (\varsigma ^{-}_{j},\omega (\varsigma ^{-}_{j})) ),\quad \varsigma \in (\varsigma _{i},\varsigma _{i+1}], i = 1,\dots , m. \end{cases} $$
(19)
Clearly, on a discrete finite set, (19) is a collection of summation operators. Further, the continuity of \(\Xi _{j}\), \(\Phi _{j}\), \(\mathcal{F}\), and G implies that \(\Lambda _{\sigma }\) is completely continuous.
Case 2: Assume that all the points of \(\mathbb{T}\) are dense, i.e., \(\mathbb{T}\) is continuous. Now, let \(\varsigma _{{f}_{1}}, \varsigma _{{f}_{2}}\in (\varsigma _{i}, \varsigma _{i+1}]\), \(i = 1,\dots , m\), such that \(\varsigma _{{f}_{1}}<\varsigma _{{f}_{2}}\), then
$$\begin{aligned} &\bigl\Vert \Lambda _{\sigma } \bigl(\omega (\varsigma _{f_{2}}) \bigr)-\Lambda _{ \sigma } \bigl({\omega }(\varsigma _{f_{1}}) \bigr) \bigr\Vert \\ &\quad \leq \Biggl\| \sum_{j=1}^{i} \bigl[\Xi _{j}\bigl(\omega (\varsigma _{{f_{2}}^{-}_{j}})\bigr)-\Xi _{j}\bigl({{ \omega }}(\varsigma _{{f_{1}}^{-}_{j}})\bigr) \bigr] \\ &\qquad {}+\sum_{j=1}^{i} \bigl[\Phi _{j} \bigl(\varsigma _{{f_{2}}^{-}_{j}}, \omega (\varsigma _{{f_{2}}^{-}_{j}})\bigr)-\Phi _{j} \bigl(\varsigma _{{f_{1}}^{-}_{j}},{{ \omega }}(\varsigma _{{f_{1}}^{-}_{j}})\bigr) \bigr] \\ &\qquad {}+ \biggl[ \biggl( \int _{\varsigma _{0}}^{\varsigma _{f_{2}}}(\varsigma _{f_{2}}-s)^{ \sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{\sigma } \bigr) \biggl(\mathcal{F}\bigl(s,\omega (s)\bigr) \\ &\qquad {}+G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr)\Delta s \biggr) \\ &\qquad {}- \biggl( \int _{\varsigma _{0}}^{\varsigma _{f_{1}}}(\varsigma _{f_{1}}-s)^{ \sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{1}}-s)^{\sigma } \bigr) \biggl(\mathcal{F}\bigl(s,\omega (s)\bigr) \\ &\qquad {}+G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr) \biggr) \biggr]\Delta s\Biggr\| \\ &\quad \leq \sum_{j=1}^{i}\bigl\| \Xi _{j}\bigl(\omega (\varsigma _{{f_{2}}^{-}_{j}})\bigr)- \Xi _{j}\bigl({{\omega }}(\varsigma _{{f_{1}}^{-}_{j}})\bigr) \bigr\Vert \\ &\qquad {}+\sum_{j=1}^{i}\bigl\| \Phi _{j} \bigl(\varsigma _{{f_{2}}^{-}_{j}}, \omega (\varsigma _{{f_{2}}^{-}_{j}})\bigr)-\Phi _{j} \bigl(\varsigma _{{f_{1}}^{-}_{j}},{{ \omega }}(\varsigma _{{f_{1}}^{-}_{j}})\bigr) \bigr\Vert \\ &\qquad {}+ \biggl\Vert \int _{\varsigma _{0}}^{\varsigma _{f_{2}}} \bigl[(\varsigma _{f_{1}}-s)^{ \sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{\sigma } \bigr)-(\varsigma _{f_{1}}-s)^{\sigma -1} E_{\sigma ,\sigma } \bigl(A( \varsigma _{f_{1}}-s)^{\sigma } \bigr) \bigr] \\ &\qquad {}\times \mathcal{F}\bigl(s,\omega (s)\bigr)\Delta s \biggr\Vert \\ &\qquad {}+ \biggl\Vert \int _{\varsigma _{0}}^{\varsigma _{f_{2}}} \bigl[(\varsigma _{f_{1}}-s)^{ \sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{\sigma } \bigr)-(\varsigma _{f_{1}}-s)^{\sigma -1} E_{\sigma ,\sigma } \bigl(A( \varsigma _{f_{1}}-s)^{\sigma } \bigr) \bigr] \\ &\qquad {}\times G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr)\Delta s \biggr\Vert \\ &\qquad {}+ \biggl\Vert \int _{\varsigma _{f_{1}}}^{\varsigma _{f_{2}}} \bigl[( \varsigma _{f_{2}}-s)^{\sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{ \sigma } \bigr) \bigr]\mathcal{F}\bigl(s,\omega (s) \bigr)\Delta s \biggr\Vert \\ &\qquad {}+ \biggl\Vert \int _{\varsigma _{f_{1}}}^{\varsigma _{f_{2}}} \bigl[( \varsigma _{f_{2}}-s)^{\sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{ \sigma } \bigr) \bigr] \\ &\qquad {}\times G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr)\Delta s \biggr\Vert . \end{aligned}$$
Clearly, we observe from the above that it approaches 0 as \(\varsigma _{f_{2}}\rightarrow \varsigma _{f_{1}}\). Hence, the operator \(\Lambda _{\sigma }\) is equicontinuous. Finally, using the Arzela–Ascoli theorem, we conclude that \(\Lambda _{\sigma }\) is completely continuous.
Case 3: Assume that \(\mathbb{T}\) involves isolated points along with dense ones, i.e., continuous and discrete. Now, utilizing Theorem 2.2 for the isolated points, we can write \(\Lambda _{\sigma }\) as the summation operator which is completely continuous (discussed in case 1). For the dense points, one can prove that \(\Lambda _{\sigma }\) is a completely continuous operator (discussed in case 2). Consequently, \(\Lambda _{\sigma }\) can be written as a sum of two operators for isolated and dense points. As a result, we know that the sum of two operators which are completely continuous is also completely continuous. Thus, the operator \(\Lambda _{\sigma }\) is a completely continuous operator. Hence, by summarizing the above three possibilities, we arrive at the conclusion that \(\Lambda _{\sigma }\) is a completely continuous operator.
Finally, let \(\beta \in [0,1]\), and there exists ω provided that \(\omega (\varsigma )=\beta (\Lambda _{\sigma }(\omega )(\varsigma ) )\). Then, for \(\varsigma \in (\varsigma _{i},\varsigma _{i+1}]\), \(i = 1,\dots , m\), one obtains
$$\begin{aligned} \bigl\Vert \omega (\varsigma ) \bigr\Vert &= \bigl\Vert \beta \bigl( \Lambda _{\sigma } \bigl( \omega (\varsigma _{f}) \bigr) \bigr) \bigr\Vert \\ &\leq \Biggl\Vert \beta \Biggl[\sum_{j=1}^{i} \Xi _{j}\bigl(\omega (\varsigma _{{f}^{-}_{j}})\bigr)+ \sum _{j=1}^{i}\Phi _{j} \bigl( \varsigma _{{f_{2}}^{-}_{j}},\omega ( \varsigma _{{f_{2}}^{-}_{j}})\bigr) \\ &\quad {}+ \int _{\varsigma _{0}}^{\varsigma _{f_{2}}}(\varsigma _{f_{2}}-s)^{ \sigma -1} E_{\sigma ,\sigma } \bigl(A(\varsigma _{f_{2}}-s)^{\sigma } \bigr) \biggl(\mathcal{F}\bigl(s,\omega (s)\bigr) \\ &\quad {}+G \biggl(s,\omega (s), \int _{s_{0}}^{s_{f}} \mathcal{F}_{1} \bigl(s,u, \omega (u)\bigr)\Delta u, \int _{s_{0}}^{s_{f}} \mathcal{F}_{2} \bigl(s,u,\omega (u)\bigr) \Delta u \biggr) \biggr)\Delta s \Biggr] \Biggr\Vert \\ &\leq \sum_{j=1}^{i}{L}_{\Xi } \Vert \omega \Vert _{\infty }+\sum_{j=1}^{i}{L}_{ \Phi } \Vert \omega \Vert _{\infty }+a_{1}+ \bigl\Vert ( \varsigma -s)^{\sigma -1} \bigr\Vert a_{2} \\ &\quad {}\times \bigl({L}_{\mathcal{F}} \Vert \omega \Vert _{\infty }+{L}_{{G}_{1}} \Vert \omega \Vert _{\infty }+{L}_{{G}_{2}}{L}_{\mathcal{\mathcal{F}}_{1}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}}) \\ &\quad {}+{L}_{{G}_{3}}{L}_{\mathcal{\mathcal{F}}_{2}} \Vert \omega \Vert _{\infty }({s_{f}}-{s_{0}})+ \widehat{M}_{G} \bigr) ({\varsigma _{f}}-{\varsigma _{0}}) \\ &\leq a_{1}+ \Biggl[\sum_{j=1}^{i}{L}_{\Xi }+ \sum_{j=1}^{i}{L}_{\Phi }+ \bigl\Vert (\varsigma -s)^{\sigma -1} \bigr\Vert a_{2} \\ &\quad {}\times \bigl({L}_{\mathcal{F}}+{L}_{{G}_{1}}+{L}_{{G}_{2}}{L}_{ \mathcal{\mathcal{F}}_{1}}({s_{f}}-{s_{0}})+{L}_{{G}_{3}}{L}_{ \mathcal{\mathcal{F}}_{2}}({s_{f}}-{s_{0}}) \bigr) ({\varsigma _{f}}-{ \varsigma _{0}}) \Biggr] \Vert \omega \Vert _{\infty } \\ &\leq a_{1}+ [N_{2}+Q_{2} ] \Vert \omega \Vert _{\infty } \\ &\leq a_{1}+Q_{3} \Vert \omega \Vert _{\infty }. \end{aligned}$$
Hence
$$ \frac{ \Vert \omega \Vert _{\infty }}{ a_{1}+Q_{3} \Vert \omega \Vert _{\infty }} \leq 1. $$
Now, from (17), we get \(\mathcal{K}>0\) such that \(\|\omega \|_{\infty }\neq \mathcal{K}\). Let us assume that
$$ \Re =\bigl\{ \omega \in \mathbb{T}, \Vert \omega \Vert _{\infty }< \mathcal{K}\bigr\} . $$
Then the operator \(\Lambda _{\sigma }:\Re \rightarrow \mathbb{T}\) is continuous as well as completely continuous. Thus, from the choice of ℜ, there is no \(\omega \in \chi (\Re )\) provided that \(\omega =\beta (\Lambda _{\sigma } ((\omega )(\varsigma ) ) )\), \(\beta \in [0,1]\).
Therefore in the light of fixed point criterion due to nonlinear alternative of Leray–Schauder, \(\Lambda _{\sigma }\) admits a fixed point which is the solution of the mixed impulsive system (1). □
We have a similar conclusion for the mixed impulsive system (2).
Theorem 3.4
The mixed impulsive system (2) admits at least one solution if assumption \((\mathbf{B})\) is satisfied and \(\mathcal{K}^{*}> 0\) exists such that
$$ a_{1}+Q^{*}_{3} \mathcal{K}^{*}< \mathcal{K}^{*}. $$
(20)
Proof
It is similar to the previous argument for \(\Psi _{\sigma }\) in Theorem 3.3. □