Database
BASIC CATEGORY THEORY
Categories
Natural transformations and the functor category
catstr
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Theorem
catstr
Description:
A category structure is a structure.
(Contributed by
Mario Carneiro
, 3-Jan-2017)
Ref
Expression
Assertion
catstr
⊢
Base
ndx
U
Hom
⁡
ndx
H
comp
⁡
ndx
·
˙
Struct
1
15
Proof
Step
Hyp
Ref
Expression
1
1nn
⊢
1
∈
ℕ
2
basendx
⊢
Base
ndx
=
1
3
4nn0
⊢
4
∈
ℕ
0
4
1nn0
⊢
1
∈
ℕ
0
5
1lt10
⊢
1
<
10
6
1
3
4
5
declti
⊢
1
<
14
7
4nn
⊢
4
∈
ℕ
8
4
7
decnncl
⊢
14
∈
ℕ
9
homndx
⊢
Hom
⁡
ndx
=
14
10
5nn
⊢
5
∈
ℕ
11
4lt5
⊢
4
<
5
12
4
3
10
11
declt
⊢
14
<
15
13
4
10
decnncl
⊢
15
∈
ℕ
14
ccondx
⊢
comp
⁡
ndx
=
15
15
1
2
6
8
9
12
13
14
strle3
⊢
Base
ndx
U
Hom
⁡
ndx
H
comp
⁡
ndx
·
˙
Struct
1
15