Solvability of infinite systems of Caputo–Hadamard fractional differential equations in the triple sequence space $$c^3(\triangle )$$

First, we introduce the concept of triple sequence space \(c^3(\triangle )\) and we define a Hausdorff measure of noncompactness (MNC) on this space. Furthermore, by using this MNC we study the existence of solutions of infinite systems of Caputo–Hadamard fractional differential equations with three point integral boundary conditions in the triple sequence space \( c^3(\triangle )\). Finally, we give an example to show the effectiveness of our main result.