postulado 51, poligonos concavos ordenados 17
If ( m, r, n ) m more that r, r greater that n, n greater or equal that one, is the data of a polygon concave ordered, then the number of sides of a line broken higher is equal to 2 ( m-n ) and the number of sides of a line broken lower is equal to 2 ( r ) and the total of sides of the polygon concave ordered is equal to 4 ( m r-2n 1 ).