Definition df-bj-pr1 37045

Description: Definition of the first projection of a class tuple. New usage is discouraged because the precise definition is generally unimportant compared to the characteristic properties bj-pr1eq 37046, bj-pr11val 37049, bj-pr21val 37057, bj-pr1ex 37050. (Contributed by BJ, 6-Apr-2019.) (New usage is discouraged.)

Assertion

Ref	Expression
df-bj-pr1	⊢ pr1 𝐴 = (∅ Proj 𝐴)

Detailed syntax breakdown of Definition df-bj-pr1

Step	Hyp	Ref	Expression
1		cA	. . 3 class 𝐴
2	1	bj-cpr1 37044	. 2 class pr1 𝐴
3		c0 4280	. . 3 class ∅
4	3, 1	bj-cproj 37034	. 2 class (∅ Proj 𝐴)
5	2, 4	wceq 1541	1 wff pr1 𝐴 = (∅ Proj 𝐴)

This definition is referenced by:  bj-pr1eq  37046  bj-pr1un  37047  bj-pr1val  37048  bj-pr1ex  37050