Definition df-bj-2upl 37034

Description: Definition of the Morse couple. See df-bj-1upl 37021. New usage is discouraged because the precise definition is generally unimportant compared to the characteristic properties bj-2upleq 37035, bj-2uplth 37044, bj-2uplex 37045, and the properties of the projections (see df-bj-pr1 37024 and df-bj-pr2 37038). (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 37033	. 2 class ⦅𝐴, 𝐵⦆
4	1	bj-c1upl 37020	. . 3 class ⦅𝐴⦆
5		c1o 8478	. . . . 5 class 1o
6	5	csn 4606	. . . 4 class {1o}
7	2	bj-ctag 36997	. . . 4 class tag 𝐵
8	6, 7	cxp 5657	. . 3 class ({1o} × tag 𝐵)
9	4, 8	cun 3929	. 2 class (⦅𝐴⦆ ∪ ({1o} × tag 𝐵))
10	3, 9	wceq 1540	1 wff ⦅𝐴, 𝐵⦆ = (⦅𝐴⦆ ∪ ({1o} × tag 𝐵))

This definition is referenced by:  bj-2upleq  37035  bj-pr21val  37036  bj-pr22val  37042  bj-2uplex  37045  bj-2upln0  37046  bj-2upln1upl  37047