Kirby calculus

Kirby calculus is a mathematical technique used in the field of low-dimensional topology, particularly in the study of 3-manifolds. It is named after Rob Kirby, who introduced this concept in a series of papers in the 1970s. The main focus of Kirby calculus is on the manipulation and understanding of 3-manifolds via the use of specific types of diagrams called Kirby diagrams or handlebody diagrams.