Theorem ccatws1cl

Description: The concatenation of a word with a singleton word is a word. (Contributed by Alexander van der Vekens, 22-Sep-2018)

	Ref	Expression
Assertion	ccatws1cl	|- ( ( W e. Word V /\ X e. V ) -> ( W ++ <" X "> ) e. Word V )

Proof

Step	Hyp	Ref	Expression
1		s1cl	|- ( X e. V -> <" X "> e. Word V )
2		ccatcl	|- ( ( W e. Word V /\ <" X "> e. Word V ) -> ( W ++ <" X "> ) e. Word V )
3	1 2	sylan2	|- ( ( W e. Word V /\ X e. V ) -> ( W ++ <" X "> ) e. Word V )