Theorem 1lt4

Description: 1 is less than 4. (Contributed by Mario Carneiro, 15-Sep-2013)

	Ref	Expression
Assertion	1lt4	$$⊢1<4$$

Proof

Step	Hyp	Ref	Expression
1		1lt2	$$⊢1<2$$
2		2lt4	$$⊢2<4$$
3		1re	$$⊢1\in ℝ$$
4		2re	$$⊢2\in ℝ$$
5		4re	$$⊢4\in ℝ$$
6	3 4 5	lttri	$$⊢\left(1<2\wedge 2<4\right)\to 1<4$$
7	1 2 6	mp2an	$$⊢1<4$$