Definition df-bj-2upl 36977

Description: Definition of the Morse couple. See df-bj-1upl 36964. New usage is discouraged because the precise definition is generally unimportant compared to the characteristic properties bj-2upleq 36978, bj-2uplth 36987, bj-2uplex 36988, and the properties of the projections (see df-bj-pr1 36967 and df-bj-pr2 36981). (Contributed by BJ, 6-Oct-2018.) (New usage is discouraged.)

Assertion

Ref	Expression
df-bj-2upl	⊢ ⦅𝐴, 𝐵⦆ = (⦅𝐴⦆ ∪ ({1o} × tag 𝐵))

Detailed syntax breakdown of Definition df-bj-2upl

Step	Hyp	Ref	Expression
1		cA	. . 3 class 𝐴
2		cB	. . 3 class 𝐵
3	1, 2	bj-c2uple 36976	. 2 class ⦅𝐴, 𝐵⦆
4	1	bj-c1upl 36963	. . 3 class ⦅𝐴⦆
5		c1o 8515	. . . . 5 class 1o
6	5	csn 4648	. . . 4 class {1o}
7	2	bj-ctag 36940	. . . 4 class tag 𝐵
8	6, 7	cxp 5698	. . 3 class ({1o} × tag 𝐵)
9	4, 8	cun 3974	. 2 class (⦅𝐴⦆ ∪ ({1o} × tag 𝐵))
10	3, 9	wceq 1537	1 wff ⦅𝐴, 𝐵⦆ = (⦅𝐴⦆ ∪ ({1o} × tag 𝐵))

This definition is referenced by:  bj-2upleq  36978  bj-pr21val  36979  bj-pr22val  36985  bj-2uplex  36988  bj-2upln0  36989  bj-2upln1upl  36990