Description: Membership in the span of a singleton. (Contributed by NM, 3-Jun-2004) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypothesis | spansn.1 | |
|
Assertion | elspansni | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | spansn.1 | |
|
2 | 1 | spansni | |
3 | 2 | eleq2i | |
4 | 1 | h1de2ci | |
5 | 3 4 | bitri | |