theorem Th20: :: JORDAN5C:20
for f being FinSequence of (TOP-REAL 2)
for Q being Subset of (TOP-REAL 2)
for i being Nat st L~ f meets Q & Q is closed & f is being_S-Seq & 1 <= i & i + 1 <= len f & Last_Point ((L~ f),(f /. 1),(f /. (len f)),Q) in LSeg (f,i) holds
Last_Point ((L~ f),(f /. 1),(f /. (len f)),Q) = Last_Point ((LSeg (f,i)),(f /. i),(f /. (i + 1)),Q)