In this paper, we study a strong k-deformation retract derived from a relative k-homotopy and investigate its properties in relation to both a k-homotopic thinning and the k-fundamental group. Moreover, we show that the k-fundamental group of a wedge product of closed k-curves not k-contractible is a free group by the use of some properties of both a strong k-deformation retract and a digital covering. Finally, we write an algorithm for calculating the k-fundamental group of a dosed k-curve by the use of a k-homotopic thinning.
digital imagedigital k-graph$(k_0k_1)$-homeomorphism$(k_0k_1)$-isomorphismstrongly local $(k_0k_1)$-isomorphismk-fundamental groupsimple k-curve pointsimple k-pointk-thinning algorithmsimply k-connectedk-homotopy equivalence$(k_0k_1)$-homotopy equivalencek-homotopic thinningstrong k-defprmation retractdigital coveringdiscrete topologydigital topology
