Description: A singleton of an ordered pair (with 0 as first component) is a word. (Contributed by AV, 23-Nov-2018) (Proof shortened by AV, 18-Apr-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | snopiswrd | |- ( S e. V -> { <. 0 , S >. } e. Word V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0zd | |- ( S e. V -> 0 e. ZZ ) |
|
2 | id | |- ( S e. V -> S e. V ) |
|
3 | 1 2 | fsnd | |- ( S e. V -> { <. 0 , S >. } : { 0 } --> V ) |
4 | fzo01 | |- ( 0 ..^ 1 ) = { 0 } |
|
5 | 4 | feq2i | |- ( { <. 0 , S >. } : ( 0 ..^ 1 ) --> V <-> { <. 0 , S >. } : { 0 } --> V ) |
6 | 3 5 | sylibr | |- ( S e. V -> { <. 0 , S >. } : ( 0 ..^ 1 ) --> V ) |
7 | iswrdi | |- ( { <. 0 , S >. } : ( 0 ..^ 1 ) --> V -> { <. 0 , S >. } e. Word V ) |
|
8 | 6 7 | syl | |- ( S e. V -> { <. 0 , S >. } e. Word V ) |