Abstract
Recently, the fixed-circle problems have been studied with different approaches as an
interesting and geometric generalization. In this paper, we present some solutions to an open
problem CC: what is (are) the condition(s) to make any circle Cv0,σ as the common fixed circle for two
(or more than two) self-mappings? To do this, we modify some known contractions which are used
in fixed-point theorems such as the Hardy–Rogers-type contraction, Kannan-type contraction, etc.