theorem :: C0SP2:19

for X being non empty compact TopSpace
for F, G, H being Point of (R_Normed_Algebra_of_ContinuousFunctions X)
for f, g, h being RealMap of X st f = F & g = G & h = H holds
( H = F - G iff for x being Element of X holds h . x = (f . x) - (g . x) )