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 e. X /\ B e. X ) -> <" A B "> e. Word X ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl | |- ( ( A e. X /\ B e. X ) -> A e. X ) |
|
2 | simpr | |- ( ( A e. X /\ B e. X ) -> B e. X ) |
|
3 | 1 2 | s2cld | |- ( ( A e. X /\ B e. X ) -> <" A B "> e. Word X ) |