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Metamath Proof Explorer


Theorem s2cl

Description: A doubleton word is a word. (Contributed by Stefan O'Rear, 23-Aug-2015) (Revised by Mario Carneiro, 26-Feb-2016)

Ref Expression
Assertion s2cl A X B X ⟨“ AB ”⟩ Word X

Proof

Step Hyp Ref Expression
1 simpl A X B X A X
2 simpr A X B X B X
3 1 2 s2cld A X B X ⟨“ AB ”⟩ Word X