Metamath Proof Explorer


Theorem ccats1val1

Description: Value of a symbol in the left half of a word concatenated with a single symbol. (Contributed by Alexander van der Vekens, 5-Aug-2018) (Revised by JJ, 20-Jan-2024)

Ref Expression
Assertion ccats1val1 WWordVI0..^WW++⟨“S”⟩I=WI

Proof

Step Hyp Ref Expression
1 s1cli ⟨“S”⟩WordV
2 ccatval1 WWordV⟨“S”⟩WordVI0..^WW++⟨“S”⟩I=WI
3 1 2 mp3an2 WWordVI0..^WW++⟨“S”⟩I=WI