Database
BASIC TOPOLOGY
Metric spaces
Path homotopy
phtpyhtpy
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phtpycn
Metamath Proof Explorer
Ascii
Unicode
Theorem
phtpyhtpy
Description:
A path homotopy is a homotopy.
(Contributed by
Mario Carneiro
, 23-Feb-2015)
Ref
Expression
Hypotheses
isphtpy.2
⊢
φ
→
F
∈
II
Cn
J
isphtpy.3
⊢
φ
→
G
∈
II
Cn
J
Assertion
phtpyhtpy
⊢
φ
→
F
PHtpy
⁡
J
G
⊆
F
II
Htpy
J
G
Proof
Step
Hyp
Ref
Expression
1
isphtpy.2
⊢
φ
→
F
∈
II
Cn
J
2
isphtpy.3
⊢
φ
→
G
∈
II
Cn
J
3
1
2
isphtpy
⊢
φ
→
h
∈
F
PHtpy
⁡
J
G
↔
h
∈
F
II
Htpy
J
G
∧
∀
s
∈
0
1
0
h
s
=
F
⁡
0
∧
1
h
s
=
F
⁡
1
4
simpl
⊢
h
∈
F
II
Htpy
J
G
∧
∀
s
∈
0
1
0
h
s
=
F
⁡
0
∧
1
h
s
=
F
⁡
1
→
h
∈
F
II
Htpy
J
G
5
3
4
syl6bi
⊢
φ
→
h
∈
F
PHtpy
⁡
J
G
→
h
∈
F
II
Htpy
J
G
6
5
ssrdv
⊢
φ
→
F
PHtpy
⁡
J
G
⊆
F
II
Htpy
J
G