Metamath Proof Explorer


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