Abacus of a partition (source code)

= Abacus of a partition

= Partition abacus
{synonym}

An $e$-runner abacus arranges the nonnegative <integers> by their residues modulo $e$ and places beads at the positions in a beta set. Moving a bead up one place on its runner removes a <rim hook> of length $e$, provided the destination is empty.

An abacus represents the <beta set of a partition> by beads at <integer> positions. Positions with the same residue modulo the chosen runner count lie on one runner; moving a bead to an empty position above it represents the corresponding rim-hook removal.