let K be non empty doubleLoopStr ; for V being non empty ModuleStr over K holds
( addLoopStr(# the carrier of (opp V), the addF of (opp V), the ZeroF of (opp V) #) = addLoopStr(# the carrier of V, the addF of V, the ZeroF of V #) & ( for x being set holds
( x is Vector of V iff x is Vector of (opp V) ) ) )
let V be non empty ModuleStr over K; ( addLoopStr(# the carrier of (opp V), the addF of (opp V), the ZeroF of (opp V) #) = addLoopStr(# the carrier of V, the addF of V, the ZeroF of V #) & ( for x being set holds
( x is Vector of V iff x is Vector of (opp V) ) ) )
reconsider p = ~ the lmult of V as Function of [: the carrier of V, the carrier of (opp K):], the carrier of V ;
A1:
opp V = RightModStr(# the carrier of V, the addF of V,(0. V),p #)
by Def2;
hence
addLoopStr(# the carrier of (opp V), the addF of (opp V), the ZeroF of (opp V) #) = addLoopStr(# the carrier of V, the addF of V, the ZeroF of V #)
; for x being set holds
( x is Vector of V iff x is Vector of (opp V) )
let x be set ; ( x is Vector of V iff x is Vector of (opp V) )
thus
( x is Vector of V iff x is Vector of (opp V) )
by A1; verum