let f be non empty one-to-one unfolded s.n.c. FinSequence of (TOP-REAL 2); for g being non trivial one-to-one unfolded s.n.c. FinSequence of (TOP-REAL 2)
for i, j being Nat st i < len f & 1 < i holds
for x being Point of (TOP-REAL 2) st x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j)) holds
x <> f /. 1
let g be non trivial one-to-one unfolded s.n.c. FinSequence of (TOP-REAL 2); for i, j being Nat st i < len f & 1 < i holds
for x being Point of (TOP-REAL 2) st x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j)) holds
x <> f /. 1
let i, j be Nat; ( i < len f & 1 < i implies for x being Point of (TOP-REAL 2) st x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j)) holds
x <> f /. 1 )
assume that
A1:
i < len f
and
A2:
1 < i
; for x being Point of (TOP-REAL 2) st x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j)) holds
x <> f /. 1
A3:
1 < i + 1
by A2, XREAL_1:29;
A4:
(LSeg (f,i)) /\ (rng f) = {(f /. i),(f /. (i + 1))}
by A1, A2, Th32;
i + 1 <= len f
by A1, NAT_1:13;
then A5:
i + 1 in dom f
by A3, FINSEQ_3:25;
A6:
LSeg ((f ^' g),i) = LSeg (f,i)
by A1, Th28;
let x be Point of (TOP-REAL 2); ( x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j)) implies x <> f /. 1 )
assume
x in (LSeg ((f ^' g),i)) /\ (LSeg ((f ^' g),j))
; x <> f /. 1
then A7:
x in LSeg (f,i)
by A6, XBOOLE_0:def 4;
A8:
1 in dom f
by FINSEQ_5:6;
assume A9:
x = f /. 1
; contradiction
x = f . 1
by A9, A8, PARTFUN1:def 6;
then
x in rng f
by A8, FUNCT_1:3;
then
x in (LSeg (f,i)) /\ (rng f)
by A7, XBOOLE_0:def 4;
then A10:
( x = f /. i or x = f /. (i + 1) )
by A4, TARSKI:def 2;
i in dom f
by A1, A2, FINSEQ_3:25;
hence
contradiction
by A2, A9, A8, A10, A3, A5, PARTFUN2:10; verum