ON A CLASSIC THEOREM OF COMBINATORICS AND THE REFLECTION PRINCIPLE.

Pedro Henrique GODINHO[1]

§ ABSTRACT: By the use of argument
based on Feller( 1968) to diagonal steps we presents a Theorem of Ballots
demonstration. Later, using only reasoning and the reflection principle
straightforward we show that number of parts from (0, 0) to (m, n), m>n, not
crossing the line x = y is given by ( FÓRMULA ), which was obtained by others
researchers making use oh sophisticated tools of Combinatorics.

§ KEYWORDS: Latticepaths; Ballot
Theorem; reflection principle.

[1] Departamento de Psicologia Experimental e do trabalho – Campus Assis – UNESP – 19800-000 – Assis – SP.