Metamath Proof Explorer


Definition df-bnj14

Description: Define the function giving: the class of all elements of A that are "smaller" than X according to R . (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Assertion df-bnj14 pred X A R = y A | y R X

Detailed syntax breakdown

Step Hyp Ref Expression
0 cX class X
1 cA class A
2 cR class R
3 1 2 0 c-bnj14 class pred X A R
4 vy setvar y
5 4 cv setvar y
6 5 0 2 wbr wff y R X
7 6 4 1 crab class y A | y R X
8 3 7 wceq wff pred X A R = y A | y R X