for n, k being Nat
for Affn being affinely-independent Subset of (TOP-REAL n)
for Ak being Subset of (TOP-REAL k)
for EN being Enumeration of Affn
for B being Subset of ((TOP-REAL n) | (Affin Affn)) st k < card Affn & B = { pnA where pnA is Element of ((TOP-REAL n) | (Affin Affn)) : (pnA |-- EN) | k in Ak } holds
( Ak is closed iff B is closed )