let AFV be WeakAffVect; for o being Element of AFV
for a being Element of (GroupVect AFV,o)
for a9 being Element of AFV st a = a9 holds
- a = (Pcom o) . a9
let o be Element of AFV; for a being Element of (GroupVect AFV,o)
for a9 being Element of AFV st a = a9 holds
- a = (Pcom o) . a9
let a be Element of (GroupVect AFV,o); for a9 being Element of AFV st a = a9 holds
- a = (Pcom o) . a9
let a9 be Element of AFV; ( a = a9 implies - a = (Pcom o) . a9 )
assume A1:
a = a9
; - a = (Pcom o) . a9
reconsider aa = (Pcom o) . a9 as Element of (GroupVect AFV,o) ;
( Pcom o,o = o & o,a9 // Pcom o,a9, Pcom o,o )
by Th35, Th39;
then A2:
Padd o,a9,(Pcom o,a9) = o
by Def5;
a + aa =
(Padd o) . a,(Pcom o,a9)
by Def8
.=
0. (GroupVect AFV,o)
by A1, A2, Def7
;
hence
- a = (Pcom o) . a9
by RLVECT_1:def 13; verum