is an expression that computes a strict upper bound of chess positions. The expression includes many illegal positions, and I intend to refine the expression in time.
This is a slightly optimized version of second expression from my paper "Of Games Greater than Ours:..." seen here:
https://docs.google.com/document/d/1UWJC7tDZ8oAECuALFpj7aFKycrjLjSlN7t3B_SGteis/edit?usp=sharing
is an expression that counts all of the various unique piece combinations if chess had an arbitrary number of piece types and each piece type had an arbitrary number of duplications.
This algorithm has other applications, but the chess applications was its original inspiration.
This is the first and main expression found in the paper in the link above.