Metamath Proof Explorer


Theorem konigsbergssiedgwpr

Description: Each subset of the indexed edges of the Königsberg graph G is a word over the pairs of vertices. (Contributed by AV, 28-Feb-2021)

Ref Expression
Hypotheses konigsberg.v ⊢ V = 0 … 3
konigsberg.e ⊢ E = ⟨“ 0 1 0 2 0 3 1 2 1 2 2 3 2 3 ”⟩
konigsberg.g ⊢ G = V E
Assertion konigsbergssiedgwpr ⊢ A ∈ Word V ∧ B ∈ Word V ∧ E = A ++ B → A ∈ Word x ∈ 𝒫 V | x = 2

Proof

Step Hyp Ref Expression
1 konigsberg.v ⊢ V = 0 … 3
2 konigsberg.e ⊢ E = ⟨“ 0 1 0 2 0 3 1 2 1 2 2 3 2 3 ”⟩
3 konigsberg.g ⊢ G = V E
4 1 2 3 konigsbergiedgw ⊢ E ∈ Word x ∈ 𝒫 V | x = 2
5 4 jctr ⊢ E = A ++ B → E = A ++ B ∧ E ∈ Word x ∈ 𝒫 V | x = 2
6 ccatrcl1 ⊢ A ∈ Word V ∧ B ∈ Word V ∧ E = A ++ B ∧ E ∈ Word x ∈ 𝒫 V | x = 2 → A ∈ Word x ∈ 𝒫 V | x = 2
7 5 6 syl3an3 ⊢ A ∈ Word V ∧ B ∈ Word V ∧ E = A ++ B → A ∈ Word x ∈ 𝒫 V | x = 2