let J1, J2 be SetSequence of X; :: thesis: ( ( for n being Element of NAT holds J1 . n = Union (Shift_Seq (A,n)) ) & ( for n being Element of NAT holds J2 . n = Union (Shift_Seq (A,n)) ) implies J1 = J2 )
assume that
A8: for n being Element of NAT holds J1 . n = Union (Shift_Seq (A,n)) and
A9: for n being Element of NAT holds J2 . n = Union (Shift_Seq (A,n)) ; :: thesis: J1 = J2
for n being Element of NAT holds J1 . n = J2 . n

proof

let n be Element of NAT ; :: thesis: J1 . n = J2 . n
J1 . n = Union (Shift_Seq (A,n)) by A8;
hence J1 . n = J2 . n by A9; :: thesis: verum

end;

then for n being set st n in NAT holds
J1 . n = J2 . n ;
hence J1 = J2 by FUNCT_2:18; :: thesis: verum