Metamath Proof Explorer


Theorem upgr1wlkdlem2

Description: Lemma 2 for upgr1wlkd . (Contributed by AV, 22-Jan-2021)

Ref Expression
Hypotheses upgr1wlkd.p ⊢ P = ⟨“ XY ”⟩
upgr1wlkd.f ⊢ F = ⟨“ J ”⟩
upgr1wlkd.x ⊢ φ → X ∈ Vtx ⁡ G
upgr1wlkd.y ⊢ φ → Y ∈ Vtx ⁡ G
upgr1wlkd.j ⊢ φ → iEdg ⁡ G ⁡ J = X Y
Assertion upgr1wlkdlem2 ⊢ φ ∧ X ≠ Y → X Y ⊆ iEdg ⁡ G ⁡ J

Proof

Step Hyp Ref Expression
1 upgr1wlkd.p ⊢ P = ⟨“ XY ”⟩
2 upgr1wlkd.f ⊢ F = ⟨“ J ”⟩
3 upgr1wlkd.x ⊢ φ → X ∈ Vtx ⁡ G
4 upgr1wlkd.y ⊢ φ → Y ∈ Vtx ⁡ G
5 upgr1wlkd.j ⊢ φ → iEdg ⁡ G ⁡ J = X Y
6 ssid ⊢ X Y ⊆ X Y
7 sseq2 ⊢ iEdg ⁡ G ⁡ J = X Y → X Y ⊆ iEdg ⁡ G ⁡ J ↔ X Y ⊆ X Y
8 7 adantl ⊢ φ ∧ X ≠ Y ∧ iEdg ⁡ G ⁡ J = X Y → X Y ⊆ iEdg ⁡ G ⁡ J ↔ X Y ⊆ X Y
9 6 8 mpbiri ⊢ φ ∧ X ≠ Y ∧ iEdg ⁡ G ⁡ J = X Y → X Y ⊆ iEdg ⁡ G ⁡ J
10 5 9 mpidan ⊢ φ ∧ X ≠ Y → X Y ⊆ iEdg ⁡ G ⁡ J