Description: 1 is less than 8. (Contributed by Mario Carneiro, 15-Sep-2013)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 1lt8 | |- 1 < 8 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 1lt2 | |- 1 < 2 | |
| 2 | 2lt8 | |- 2 < 8 | |
| 3 | 1re | |- 1 e. RR | |
| 4 | 2re | |- 2 e. RR | |
| 5 | 8re | |- 8 e. RR | |
| 6 | 3 4 5 | lttri | |- ( ( 1 < 2 /\ 2 < 8 ) -> 1 < 8 ) | 
| 7 | 1 2 6 | mp2an | |- 1 < 8 |