theorem Th75: :: FACIRC_1:75
for x, y, c being non pair object holds
( InputVertices (MajorityStr (x,y,c)) = {x,y,c} & InnerVertices (MajorityStr (x,y,c)) = {[<*x,y*>,'&'],[<*y,c*>,'&'],[<*c,x*>,'&']} \/ {(MajorityOutput (x,y,c))} )