theorem Th37: :: POLYFORM:39

for p being polyhedron
for k being Integer
for c, d being Element of (k -chain-space p)
for x being Element of (k - 1) -polytopes p holds Sum ((incidence-sequence (x,c)) + (incidence-sequence (x,d))) = (Sum (incidence-sequence (x,c))) + (Sum (incidence-sequence (x,d)))