let X be set ; :: thesis: for L being List of X
for O being Operation of X holds L WHEREeq (O,0) = L WHERE (NOT O)

let L be List of X; :: thesis: for O being Operation of X holds L WHEREeq (O,0) = L WHERE (NOT O)
let O be Operation of X; :: thesis: L WHEREeq (O,0) = L WHERE (NOT O)
thus L WHEREeq (O,0) c= L WHERE (NOT O) :: according to XBOOLE_0:def 10 :: thesis: L WHERE (NOT O) c= L WHEREeq (O,0)
proof
let z be object ; :: according to TARSKI:def 3 :: thesis: ( not z in L WHEREeq (O,0) or z in L WHERE (NOT O) )
assume z in L WHEREeq (O,0) ; :: thesis: z in L WHERE (NOT O)
then consider x being Element of X such that
A1: ( z = x & card (x . O) = 0 & x in L ) ;
x . O = {} by A1;
then x nin dom O by RELAT_1:170;
then [x,x] in NOT O by ;
then x,x in NOT O ;
hence z in L WHERE (NOT O) by A1; :: thesis: verum
end;
let z be object ; :: according to TARSKI:def 3 :: thesis: ( not z in L WHERE (NOT O) or z in L WHEREeq (O,0) )
assume z in L WHERE (NOT O) ; :: thesis: z in L WHEREeq (O,0)
then consider x being Element of X such that
A2: ( z = x & ex y being Element of X st
( x,y in NOT O & x in L ) ) ;
consider y being Element of X such that
A3: ( x,y in NOT O & x in L ) by A2;
[x,y] in NOT O by A3;
then ( x = y & x in X & x nin dom O ) by Th36;
then x . O = {} by RELAT_1:170;
then card (x . O) = 0 ;
hence z in L WHEREeq (O,0) by A2; :: thesis: verum