Minimal generating sets of moves for diagrams of isotopic knots and spatial trivalent graphs

Abstract

Polyak proved that all oriented versions of Reidemeister moves for knot and link diagrams can be generated by a set of just four oriented Reidemeister moves, and that no fewer than four oriented Reidemeister moves generate them all. We refer to a set containing four oriented Reidemeister moves that collectively generate all of the other oriented Reidemeister moves as a minimal generating set. Polyak also proved that a certain set containing two Reidemeister moves of type 1, one move of type 2 and one move of type 3 form a minimal generating set for all oriented Reidemeister moves. We expand upon Polyak’s work by providing an additional eleven minimal, 4-element, generating sets of oriented Reidemeister moves, and we prove that these 12 sets represent all possible minimal generating sets of oriented Reidemeister moves. We also consider the Reidemeister-type moves that relate oriented spatial trivalent graph diagrams with trivalent vertices that are sources and sinks and prove that a minimal generating set of oriented Reidemeister-type moves for spatial trivalent graph diagrams contains 10 moves.