Metamath Proof Explorer


Theorem ltnrd

Description: 'Less than' is irreflexive. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis ltd.1 φA
Assertion ltnrd φ¬A<A

Proof

Step Hyp Ref Expression
1 ltd.1 φA
2 ltnr A¬A<A
3 1 2 syl φ¬A<A