Description: Singleton with character out of range S is not an increasing sequence for that range. (Contributed by Ender Ting, 22-Nov-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | singoutnupword.1 | |- A e. _V | |
| Assertion | singoutnupword | |- ( -. A e. S -> -. <" A "> e. UpWord S ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | singoutnupword.1 | |- A e. _V | |
| 2 | 1 | singoutnword | |- ( -. A e. S -> -. <" A "> e. Word S ) | 
| 3 | upwordisword | |- ( <" A "> e. UpWord S -> <" A "> e. Word S ) | |
| 4 | 2 3 | nsyl | |- ( -. A e. S -> -. <" A "> e. UpWord S ) |