Quandles

Quandles and their kin--kei racks, biquandles, and biracks--are algebraic structures whose axioms encode the movement of knots in space, say Elhamdadi and Nelson, in the same way that groups encode symmetry and orthogonal transformations encode rigid motion. They introduce quandle theory to readers who are comfortable with linear algebra and basic set theory but may have no previous exposure to abstract algebra, knot theory, or topology. They cover knots and links, quandles, quandles and groups, generalizations of quandles, enhancements, and generalized knots and links.