Induced writhe in linked polygons

We consider a pair of polygons on the simple cubic lattice forming a link of specified type. We investigate the mean writhe of the polygons as a function of the number of edges in each polygon, and of the link type. Although two unknotted polygons which are linked as a Hopf link have zero mean writhe, we show that other torus links induce writhe in the polygons. We also consider non-torus links, including a link in which one polygon is knotted.