Metamath Proof Explorer


Theorem s7cli

Description: A length 7 string is a word. (Contributed by Mario Carneiro, 26-Feb-2016)

Ref Expression
Assertion s7cli
|- <" A B C D E F G "> e. Word _V

Proof

Step Hyp Ref Expression
1 df-s7
 |-  <" A B C D E F G "> = ( <" A B C D E F "> ++ <" G "> )
2 s6cli
 |-  <" A B C D E F "> e. Word _V
3 1 2 cats1cli
 |-  <" A B C D E F G "> e. Word _V