Metamath Proof Explorer


Theorem ltnrd

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

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

Proof

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