Pigeon Hole Principle

Wojciech A. Trybulec

Warsaw University

Summary.

We introduce the notion of a predicate that states that a function is one-to-one at a given element of its domain (i.e. counterimage of image of the element is equal to its singleton). We also introduce some rather technical functors concerning finite sequences: the lowest index of the given element of the range of the finite sequence, the substring preceding (and succeeding) the first occurrence of given element of the range. At the end of the article we prove the pigeon hole principle.

MML Identifier: FINSEQ_4

Contents (PDF format)

Bibliography

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