self-mapping
function that maps a set into itself
logical negation
operation that takes a proposition p to another proposition "not p", written ¬p, which is interpreted intuitively as being true when p is false, and false when p is true; unary (single-argument) logical connective
opposite number
number that, when added to the original number, yields zero
measure-preserving dynamical system
subject of study in ergodic theory
antecessor
operation on ordinal numbers
identity function
function that always returns the same value that was used as its argument
successor function
elementary operation on a natural number
involution
function that is its own inverse
successor ordinal
smallest ordinal following a given ordinal