Metamath Proof Explorer


Theorem wrdlenge2n0

Description: A word with length at least 2 is not empty. (Contributed by AV, 18-Jun-2018) (Proof shortened by AV, 14-Oct-2018)

Ref Expression
Assertion wrdlenge2n0 W Word V 2 W W

Proof

Step Hyp Ref Expression
1 1red W Word V 1
2 2re 2
3 2 a1i W Word V 2
4 lencl W Word V W 0
5 4 nn0red W Word V W
6 1 3 5 3jca W Word V 1 2 W
7 6 adantr W Word V 2 W 1 2 W
8 simpr W Word V 2 W 2 W
9 1lt2 1 < 2
10 8 9 jctil W Word V 2 W 1 < 2 2 W
11 ltleletr 1 2 W 1 < 2 2 W 1 W
12 7 10 11 sylc W Word V 2 W 1 W
13 wrdlenge1n0 W Word V W 1 W
14 13 adantr W Word V 2 W W 1 W
15 12 14 mpbird W Word V 2 W W