Compact self-avoiding circuits on two-dimensional lattices

Close-packed self-avoiding walks and circuits, as models for condensed polymer phases, are studied on the square-planar and honeycomb lattices. Exact solutions for strips from these lattices are obtained via transfer matrix methods. Extrapolations are made for the leading asymptotic terms in the count of compact conformations on the square-planar lattice. The leading asymptotic term for each lattice is bounded from below, and it is noted that boundary effects can be important.