objective: one of the main cultural issues in universities is relationships between male and female students. due to the adverse consequences of this issue, explaining of the beyond the causes of friendship with opposite-sex, is one of the first steps in planning for youth issues. methods: this qualitative research was conducted based on content analysis. nineteen female university students wer...

In this paper we consider planar polygons with parallel opposite sides. This type of polygons can be regarded as discretizations of closed convex planar curves by taking tangent lines at samples with pairwise parallel tangents. For this class of polygons, we define discrete versions of the area evolute, central symmetry set, equidistants and area parallels and show that they behave quite simila...