theorem Th6: :: TIETZE_2:7

for n, i being Nat
for p, q being Point of (TOP-REAL n)
for r being Real
for R being real-valued FinSequence st i in Seg n & q in ClosedHypercube (p,R) & r in [.((p . i) - (R . i)),((p . i) + (R . i)).] holds
q +* (i,r) in ClosedHypercube (p,R)