let AFV be WeakAffVect; for o being Element of AFV
for a being Element of (GroupVect AFV,o) holds a + (0. (GroupVect AFV,o)) = a
let o be Element of AFV; for a being Element of (GroupVect AFV,o) holds a + (0. (GroupVect AFV,o)) = a
let a be Element of (GroupVect AFV,o); a + (0. (GroupVect AFV,o)) = a
reconsider a9 = a as Element of AFV ;
reconsider x9 = a + (0. (GroupVect AFV,o)) as Element of AFV ;
x9 = Padd o,a9,o
by Def7;
then
o,a9 // o,x9
by Def5;
hence
a + (0. (GroupVect AFV,o)) = a
by Th5; verum