Metamath Proof Explorer


Definition df-plt

Description: Define less-than ordering for posets and related structures. Unlike df-base and df-ple , this is a derived component extractor and not an extensible structure component extractor that defines the poset. (Contributed by NM, 12-Oct-2011) (Revised by Mario Carneiro, 8-Feb-2015)

Ref Expression
Assertion df-plt lt = p V p I

Detailed syntax breakdown

Step Hyp Ref Expression
0 cplt class lt
1 vp setvar p
2 cvv class V
3 cple class le
4 1 cv setvar p
5 4 3 cfv class p
6 cid class I
7 5 6 cdif class p I
8 1 2 7 cmpt class p V p I
9 0 8 wceq wff lt = p V p I