Selection in a particular order
In combinatorial mathematics , a partial permutation , or sequence without repetition , on a finite set S
is a bijection between two specified subsets of S . That is, it is defined by two subsets U and V of equal size, and a one-to-one mapping from U to V . Equivalently, it is a partial function on S that can be extended to a permutation .[ 1] [ 2]
^ Straubing, Howard (1983), "A combinatorial proof of the Cayley-Hamilton theorem", Discrete Mathematics , 43 (2–3): 273–279, doi :10.1016/0012-365X(83)90164-4 MR 0685635 ^ Ku, C. Y.; Leader, I. (2006), "An Erdős-Ko-Rado theorem for partial permutations", Discrete Mathematics 306 (1): 74–86, doi :10.1016/j.disc.2005.11.007 MR 2202076