let n2, n1, n3 be Element of NAT ; :: thesis: for S being Gene-Set
for p1, p2 being Individual of S st n2 >= len p1 holds
crossover p1,p2,n1,n2,n3 = crossover p1,p2,n1,n3
let S be Gene-Set; :: thesis: for p1, p2 being Individual of S st n2 >= len p1 holds
crossover p1,p2,n1,n2,n3 = crossover p1,p2,n1,n3
let p1, p2 be Individual of S; :: thesis: ( n2 >= len p1 implies crossover p1,p2,n1,n2,n3 = crossover p1,p2,n1,n3 )
assume A1: n2 >= len p1 ; :: thesis: crossover p1,p2,n1,n2,n3 = crossover p1,p2,n1,n3
then n2 >= len S by Def1;
then A2: n2 >= len p2 by Def1;
crossover p1,p2,n1,n2,n3 = crossover (crossover p1,p2,n1),(crossover p2,p1,n1,n2),n3 by A1, Th10
.= crossover (crossover p1,p2,n1),(crossover p2,p1,n1),n3 by A2, Th10 ;
hence crossover p1,p2,n1,n2,n3 = crossover p1,p2,n1,n3 ; :: thesis: verum