Database
BASIC ORDER THEORY
Preordered sets and directed sets
drsprs
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drsbn0
Metamath Proof Explorer
Ascii
Unicode
Theorem
drsprs
Description:
A directed set is a proset.
(Contributed by
Stefan O'Rear
, 1-Feb-2015)
Ref
Expression
Assertion
drsprs
⊢
K
∈
Dirset
→
K
∈
Proset
Proof
Step
Hyp
Ref
Expression
1
eqid
⊢
Base
K
=
Base
K
2
eqid
⊢
≤
K
=
≤
K
3
1
2
isdrs
⊢
K
∈
Dirset
↔
K
∈
Proset
∧
Base
K
≠
∅
∧
∀
x
∈
Base
K
∀
y
∈
Base
K
∃
z
∈
Base
K
x
≤
K
z
∧
y
≤
K
z
4
3
simp1bi
⊢
K
∈
Dirset
→
K
∈
Proset