Metamath Proof Explorer


Theorem htpyid

Description: A homotopy from a function to itself. (Contributed by Mario Carneiro, 23-Feb-2015)

Ref Expression
Hypotheses htpyid.1 G = x X , y 0 1 F x
htpyid.2 φ J TopOn X
htpyid.4 φ F J Cn K
Assertion htpyid φ G F J Htpy K F

Proof

Step Hyp Ref Expression
1 htpyid.1 G = x X , y 0 1 F x
2 htpyid.2 φ J TopOn X
3 htpyid.4 φ F J Cn K
4 iitopon II TopOn 0 1
5 4 a1i φ II TopOn 0 1
6 2 5 cnmpt1st φ x X , y 0 1 x J × t II Cn J
7 2 5 6 3 cnmpt21f φ x X , y 0 1 F x J × t II Cn K
8 1 7 eqeltrid φ G J × t II Cn K
9 simpr φ s X s X
10 0elunit 0 0 1
11 fveq2 x = s F x = F s
12 eqidd y = 0 F s = F s
13 fvex F s V
14 11 12 1 13 ovmpo s X 0 0 1 s G 0 = F s
15 9 10 14 sylancl φ s X s G 0 = F s
16 1elunit 1 0 1
17 eqidd y = 1 F s = F s
18 11 17 1 13 ovmpo s X 1 0 1 s G 1 = F s
19 9 16 18 sylancl φ s X s G 1 = F s
20 2 3 3 8 15 19 ishtpyd φ G F J Htpy K F