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 | 
| 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 |