Metamath Proof Explorer


Theorem s2cli

Description: A doubleton word is a word. (Contributed by Mario Carneiro, 26-Feb-2016)

Ref Expression
Assertion s2cli ⟨“ AB ”⟩ Word V

Proof

Step Hyp Ref Expression
1 df-s2 ⟨“ AB ”⟩ = ⟨“ A ”⟩ ++ ⟨“ B ”⟩
2 s1cli ⟨“ A ”⟩ Word V
3 1 2 cats1cli ⟨“ AB ”⟩ Word V