Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Union
Supremum and infimum
infex
Next ⟩
infmin
Metamath Proof Explorer
Ascii
Unicode
Theorem
infex
Description:
An infimum is a set.
(Contributed by
AV
, 3-Sep-2020)
Ref
Expression
Hypothesis
infex.1
⊢
R
Or
A
Assertion
infex
⊢
sup
B
A
R
∈
V
Proof
Step
Hyp
Ref
Expression
1
infex.1
⊢
R
Or
A
2
id
⊢
R
Or
A
→
R
Or
A
3
2
infexd
⊢
R
Or
A
→
sup
B
A
R
∈
V
4
1
3
ax-mp
⊢
sup
B
A
R
∈
V