let V be non empty set ; for m being Element of Maps V holds m = [[(dom m),(cod m)],(m `2)]
let m be Element of Maps V; m = [[(dom m),(cod m)],(m `2)]
consider f being Element of Funcs V, A, B being Element of V such that
A1:
( m = [[A,B],f] & ( B = {} implies A = {} ) & f is Function of A,B )
by Th4;
thus
m = [[(dom m),(cod m)],(m `2)]
by A1; verum