let X be set ; for KX being SimplicialComplexStr of X
for P being Function holds subdivision (1,P,KX) = subdivision (P,KX)
let KX be SimplicialComplexStr of X; for P being Function holds subdivision (1,P,KX) = subdivision (P,KX)
let P be Function; subdivision (1,P,KX) = subdivision (P,KX)
consider F being Function such that
A1:
F . 0 = KX
and
A2:
F . 1 = subdivision (1,P,KX)
and
dom F = NAT
and
A3:
for k being Nat
for KX1 being SimplicialComplexStr of X st KX1 = F . k holds
F . (k + 1) = subdivision (P,KX1)
by Def21;
F . (0 + 1) = subdivision (P,KX)
by A1, A3;
hence
subdivision (1,P,KX) = subdivision (P,KX)
by A2; verum