Database
BASIC TOPOLOGY
Metric spaces
Path homotopy
htpycn
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Theorem
htpycn
Description:
A homotopy is a continuous function.
(Contributed by
Mario Carneiro
, 22-Feb-2015)
Ref
Expression
Hypotheses
ishtpy.1
⊢
φ
→
J
∈
TopOn
⁡
X
ishtpy.3
⊢
φ
→
F
∈
J
Cn
K
ishtpy.4
⊢
φ
→
G
∈
J
Cn
K
Assertion
htpycn
⊢
φ
→
F
J
Htpy
K
G
⊆
J
×
t
II
Cn
K
Proof
Step
Hyp
Ref
Expression
1
ishtpy.1
⊢
φ
→
J
∈
TopOn
⁡
X
2
ishtpy.3
⊢
φ
→
F
∈
J
Cn
K
3
ishtpy.4
⊢
φ
→
G
∈
J
Cn
K
4
1
2
3
ishtpy
⊢
φ
→
h
∈
F
J
Htpy
K
G
↔
h
∈
J
×
t
II
Cn
K
∧
∀
s
∈
X
s
h
0
=
F
⁡
s
∧
s
h
1
=
G
⁡
s
5
simpl
⊢
h
∈
J
×
t
II
Cn
K
∧
∀
s
∈
X
s
h
0
=
F
⁡
s
∧
s
h
1
=
G
⁡
s
→
h
∈
J
×
t
II
Cn
K
6
4
5
syl6bi
⊢
φ
→
h
∈
F
J
Htpy
K
G
→
h
∈
J
×
t
II
Cn
K
7
6
ssrdv
⊢
φ
→
F
J
Htpy
K
G
⊆
J
×
t
II
Cn
K