Metamath Proof Explorer


Theorem lttri5d

Description: Not equal and not larger implies smaller. (Contributed by Glauco Siliprandi, 11-Dec-2019)

Ref Expression
Hypotheses lttri5d.a φ A
lttri5d.b φ B
lttri5d.aneb φ A B
lttri5d.nlt φ ¬ B < A
Assertion lttri5d φ A < B

Proof

Step Hyp Ref Expression
1 lttri5d.a φ A
2 lttri5d.b φ B
3 lttri5d.aneb φ A B
4 lttri5d.nlt φ ¬ B < A
5 1 rexrd φ A *
6 2 rexrd φ B *
7 5 6 3 4 xrlttri5d φ A < B