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 e. RR
4		2re	|- 2 e. RR
5		4re	|- 4 e. RR
6	3 4 5	lttri	|- ( ( 1 < 2 /\ 2 < 4 ) -> 1 < 4 )
7	1 2 6	mp2an	|- 1 < 4