let G be non empty right_complementable add-associative right_zeroed addLoopStr ; :: thesis: for v, w being Element of holds - ((- v) + w) = (- w) + v
let v, w be Element of ; :: thesis: - ((- v) + w) = (- w) + v
thus - ((- v) + w) = (- w) + (- (- v)) by RLVECT_1:45
.= (- w) + v by RLVECT_1:30 ; :: thesis: verum