Description: The quantification of a falsehood is vacuous when true. (Contributed by NM, 26-Nov-2005) (Proof shortened by JJ, 14-Jul-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ralf0.1 | ||
Assertion | ralf0 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ralf0.1 | ||
2 | mtt | ||
3 | 1 2 | ax-mp | |
4 | 3 | albii | |
5 | eq0 | ||
6 | df-ral | ||
7 | 4 5 6 | 3bitr4ri |