Definition df-bj-pr1 32989

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 32990, bj-pr11val 32993, bj-pr21val 33001, bj-pr1ex 32994. (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 32988	. 2 class pr1 𝐴
3		c0 3915	. . 3 class ∅
4	3, 1	bj-cproj 32978	. 2 class (∅ Proj 𝐴)
5	2, 4	wceq 1483	1 wff pr1 𝐴 = (∅ Proj 𝐴)

This definition is referenced by:  bj-pr1eq  32990  bj-pr1un  32991  bj-pr1val  32992  bj-pr1ex  32994