Partitioning orthogonal polygons by extension of all edges incident to reflex vertices: lower and upper bounds on the number of pieces

Abstract

Given an orthogonal polygon P, let |Π(P)| be the number of rectangles that result when we partition P by extending the edges incident to reflex vertices towards INT(P). In Tomás, A. P., Bajuelos, A. L., Marques, F.: Approximation algorithms to minimum vertex cover problems on polygons and terrains. In P.M.A Sloot et al. (Eds): Proc. of ICCS 2003, LNCS 2657, SpringerVerlag (2003) 869-878. we showed that |Π(P)| ≤ 1 + r + r 2, where r is the number of reflex vertices of P. We shall now give sharper bounds both for maxP |Π(P)| and minP |Π(P)|. Moreover, we characterize the structure of orthogonal polygons in general position for which these new bounds are exact.