Metamath Proof Explorer

Theorem s3cli

Description: A length 3 string is a word. (Contributed by Mario Carneiro, 26-Feb-2016)

Ref Expression
Assertion s3cli 
|- <" A B C "> e. Word _V

Proof

Step Hyp Ref Expression
1 df-s3 
 |-  <" A B C "> = ( <" A B "> ++ <" C "> )
2 s2cli 
 |-  <" A B "> e. Word _V
3 1 2 cats1cli 
 |-  <" A B C "> e. Word _V