Description: A word over an alphabet is a function from an open range of nonnegative integers (of length equal to the length of the word) into the alphabet. (Contributed by Alexander van der Vekens, 30-Jul-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | iswrdb | |- ( W e. Word S <-> W : ( 0 ..^ ( # ` W ) ) --> S ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | wrdf | |- ( W e. Word S -> W : ( 0 ..^ ( # ` W ) ) --> S ) |
|
| 2 | iswrdi | |- ( W : ( 0 ..^ ( # ` W ) ) --> S -> W e. Word S ) |
|
| 3 | 1 2 | impbii | |- ( W e. Word S <-> W : ( 0 ..^ ( # ` W ) ) --> S ) |