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Database
BASIC CATEGORY THEORY
Categories
Initial, terminal and zero objects of a category
df-zeroo
Metamath Proof Explorer
Description: An object A is called a zero object provided that it is both an initial
object and a terminal object. Definition 7.7 of Adamek p. 103.
(Contributed by AV , 3-Apr-2020)
Ref
Expression
Assertion
df-zeroo
⊢ ZeroO = c ∈ Cat ⟼ InitO ⁡ c ∩ TermO ⁡ c
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
czeroo
class ZeroO
1
vc
setvar c
2
ccat
class Cat
3
cinito
class InitO
4
1
cv
setvar c
5
4 3
cfv
class InitO ⁡ c
6
ctermo
class TermO
7
4 6
cfv
class TermO ⁡ c
8
5 7
cin
class InitO ⁡ c ∩ TermO ⁡ c
9
1 2 8
cmpt
class c ∈ Cat ⟼ InitO ⁡ c ∩ TermO ⁡ c
10
0 9
wceq
wff ZeroO = c ∈ Cat ⟼ InitO ⁡ c ∩ TermO ⁡ c