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 predXAR=yA|yRX

Detailed syntax breakdown

Step Hyp Ref Expression
0 cX classX
1 cA classA
2 cR classR
3 1 2 0 c-bnj14 classpredXAR
4 vy setvary
5 4 cv setvary
6 5 0 2 wbr wffyRX
7 6 4 1 crab classyA|yRX
8 3 7 wceq wffpredXAR=yA|yRX