Description: Two ways of expressing "at most one" element in a class. (Contributed by Zhi Wang, 23-Sep-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | mosssn2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 19.45v | |
|
2 | sssn | |
|
3 | 2 | exbii | |
4 | mo0sn | |
|
5 | 1 3 4 | 3bitr4ri | |