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Description: There exists atom under a co-atom different from any two other elements. (Contributed by NM, 24-Jul-2013)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | lhpex1.l | ||
| lhpex1.a | |||
| lhpex1.h | |||
| Assertion | lhpexle2 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | lhpex1.l | ||
| 2 | lhpex1.a | ||
| 3 | lhpex1.h | ||
| 4 | 1 2 3 | lhpexle1 | |
| 5 | 1 2 3 | lhpexle1 | |
| 6 | 5 | adantr | |
| 7 | 1 2 3 | lhpexle2lem | |
| 8 | 7 | 3expa | |
| 9 | 6 8 | lhpexle1lem | |
| 10 | 3ancomb | ||
| 11 | 10 | rexbii | |
| 12 | 9 11 | sylib | |
| 13 | 4 12 | lhpexle1lem |