Description: 6 is less than 8. (Contributed by Mario Carneiro, 15-Sep-2013)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 6lt8 | ⊢ 6 < 8 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 6lt7 | ⊢ 6 < 7 | |
| 2 | 7lt8 | ⊢ 7 < 8 | |
| 3 | 6re | ⊢ 6 ∈ ℝ | |
| 4 | 7re | ⊢ 7 ∈ ℝ | |
| 5 | 8re | ⊢ 8 ∈ ℝ | |
| 6 | 3 4 5 | lttri | ⊢ ( ( 6 < 7 ∧ 7 < 8 ) → 6 < 8 ) | 
| 7 | 1 2 6 | mp2an | ⊢ 6 < 8 |