Common fixed point theorems for a weaker Meir–Keeler type function in cone metric spaces

In this work, we define a weaker Meir–Keeler type function ψ : int P ∪ { 0 } → int P ∪ { 0 } in a cone metric space, and under this weaker Meir–Keeler type function, we show the common fixed point theorems of four single-valued functions in cone metric spaces.