Metamath Proof Explorer


Theorem lpadlem1

Description: Lemma for the leftpad theorems. (Contributed by Thierry Arnoux, 7-Aug-2023)

Ref Expression
Hypothesis lpadlem1.1
|- ( ph -> C e. S )
Assertion lpadlem1
|- ( ph -> ( ( 0 ..^ ( L - ( # ` W ) ) ) X. { C } ) e. Word S )

Proof

Step Hyp Ref Expression
1 lpadlem1.1
 |-  ( ph -> C e. S )
2 fconst6g
 |-  ( C e. S -> ( ( 0 ..^ ( L - ( # ` W ) ) ) X. { C } ) : ( 0 ..^ ( L - ( # ` W ) ) ) --> S )
3 iswrdi
 |-  ( ( ( 0 ..^ ( L - ( # ` W ) ) ) X. { C } ) : ( 0 ..^ ( L - ( # ` W ) ) ) --> S -> ( ( 0 ..^ ( L - ( # ` W ) ) ) X. { C } ) e. Word S )
4 1 2 3 3syl
 |-  ( ph -> ( ( 0 ..^ ( L - ( # ` W ) ) ) X. { C } ) e. Word S )