Description: A graph without vertices is connected. (Contributed by Alexander van der Vekens, 2-Dec-2017) (Revised by AV, 15-Feb-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | 0conngr |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ral0 | ||
2 | 0ex | ||
3 | vtxval0 | ||
4 | 3 | eqcomi | |
5 | 4 | isconngr | |
6 | 2 5 | ax-mp | |
7 | 1 6 | mpbir |