let n1, n2 be Element of NAT ; for S being Gene-Set
for p1, p2 being Individual of S st n1 >= len p1 holds
crossover p1,p2,n1,n2 = crossover p1,p2,n2
let S be Gene-Set; for p1, p2 being Individual of S st n1 >= len p1 holds
crossover p1,p2,n1,n2 = crossover p1,p2,n2
let p1, p2 be Individual of S; ( n1 >= len p1 implies crossover p1,p2,n1,n2 = crossover p1,p2,n2 )
assume A1:
n1 >= len p1
; crossover p1,p2,n1,n2 = crossover p1,p2,n2
then
n1 >= len S
by Def1;
then A2:
n1 >= len p2
by Def1;
crossover p1,p2,n1,n2 = crossover p1,(crossover p2,p1,n1),n2
by A1, Th5;
hence
crossover p1,p2,n1,n2 = crossover p1,p2,n2
by A2, Th5; verum