Plans’ Periodicity Theorem for Jacobian of Circulant Graphs

Doklady Mathematics - Plans’ theorem states that, for odd n, the first homology group of the n-fold cyclic covering of the three-dimensional sphere branched over a knot is the direct product...     

Discrete analogs of Farkas and Accola’s theorems on hyperelliptic coverings of a Riemann surface of genus 2

Discrete versions of Accola and Farkas’ theorems on the hyperellipticity of coverings of a Riemann surface of genus 2 are proved.