let n1, n2, n3, n4 be Element of NAT ; :: thesis: for S being Gene-Set
for p1, p2 being Individual of S holds
( ( n1 >= len p1 & n2 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) ) & ( n1 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) ) & ( n1 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) ) & ( n2 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) ) & ( n2 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) ) & ( n3 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) ) )

let S be Gene-Set; :: thesis: for p1, p2 being Individual of S holds
( ( n1 >= len p1 & n2 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) ) & ( n1 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) ) & ( n1 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) ) & ( n2 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) ) & ( n2 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) ) & ( n3 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) ) )

let p1, p2 be Individual of S; :: thesis: ( ( n1 >= len p1 & n2 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) ) & ( n1 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) ) & ( n1 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) ) & ( n2 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) ) & ( n2 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) ) & ( n3 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) ) )
A1: ( n1 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) )
proof
assume that
A2: n1 >= len p1 and
A3: n3 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3,n4) by A2, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) by A3, Th19; :: thesis: verum
end;
A4: ( n1 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) )
proof
assume that
A5: n1 >= len p1 and
A6: n4 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3,n4) by A5, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) by A6, Th20; :: thesis: verum
end;
A7: ( n3 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) )
proof
assume that
A8: n3 >= len p1 and
A9: n4 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2,n4) by A8, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) by A9, Th20; :: thesis: verum
end;
A10: ( n2 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) )
proof
assume that
A11: n2 >= len p1 and
A12: n4 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3,n4) by A11, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) by A12, Th20; :: thesis: verum
end;
A13: ( n2 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) )
proof
assume that
A14: n2 >= len p1 and
A15: n3 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3,n4) by A14, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) by A15, Th19; :: thesis: verum
end;
( n1 >= len p1 & n2 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) )
proof
assume that
A16: n1 >= len p1 and
A17: n2 >= len p1 ; :: thesis: crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4)
crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3,n4) by A16, Th33;
hence crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) by A17, Th18; :: thesis: verum
end;
hence ( ( n1 >= len p1 & n2 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n3,n4) ) & ( n1 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n4) ) & ( n1 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n2,n3) ) & ( n2 >= len p1 & n3 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n4) ) & ( n2 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n3) ) & ( n3 >= len p1 & n4 >= len p1 implies crossover (p1,p2,n1,n2,n3,n4) = crossover (p1,p2,n1,n2) ) ) by A1, A4, A13, A10, A7; :: thesis: verum