Description: The null graph (as hypergraph) is a subgraph of all graphs. (Contributed by AV, 17-Nov-2020) (Proof shortened by AV, 28-Nov-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | 0uhgrsubgr | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 3simpa | |
|
2 | 0ss | |
|
3 | sseq1 | |
|
4 | 2 3 | mpbiri | |
5 | 4 | 3ad2ant3 | |
6 | eqid | |
|
7 | 6 | uhgrfun | |
8 | 7 | 3ad2ant2 | |
9 | edgval | |
|
10 | uhgr0vb | |
|
11 | rneq | |
|
12 | rn0 | |
|
13 | 11 12 | eqtrdi | |
14 | 10 13 | syl6bi | |
15 | 14 | ex | |
16 | 15 | pm2.43a | |
17 | 16 | a1i | |
18 | 17 | 3imp | |
19 | 9 18 | eqtrid | |
20 | egrsubgr | |
|
21 | 1 5 8 19 20 | syl112anc | |