Theorem bj-pr11val 34312

Description: Value of the first projection of a monuple. (Contributed by BJ, 6-Apr-2019.)

Assertion

Ref	Expression
bj-pr11val	⊢ pr1 ⦅𝐴⦆ = 𝐴

Proof of Theorem bj-pr11val

Step	Hyp	Ref	Expression
1		df-bj-1upl 34305	. . 3 ⊢ ⦅𝐴⦆ = ({∅} × tag 𝐴)
2		bj-pr1eq 34309	. . 3 ⊢ (⦅𝐴⦆ = ({∅} × tag 𝐴) → pr1 ⦅𝐴⦆ = pr1 ({∅} × tag 𝐴))
3	1, 2	ax-mp 5	. 2 ⊢ pr1 ⦅𝐴⦆ = pr1 ({∅} × tag 𝐴)
4		bj-pr1val 34311	. 2 ⊢ pr1 ({∅} × tag 𝐴) = if(∅ = ∅, 𝐴, ∅)
5		eqid 2821	. . 3 ⊢ ∅ = ∅
6	5	iftruei 4474	. 2 ⊢ if(∅ = ∅, 𝐴, ∅) = 𝐴
7	3, 4, 6	3eqtri 2848	1 ⊢ pr1 ⦅𝐴⦆ = 𝐴

Syntax hints:   = wceq 1533  ∅c0 4291  ifcif 4467  {csn 4561   × cxp 5548  tag bj-ctag 34281  ⦅bj-c1upl 34304  pr₁ bj-cpr1 34307

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1907  ax-6 1966  ax-7 2011  ax-8 2112  ax-9 2120  ax-10 2141  ax-11 2156  ax-12 2172  ax-ext 2793  ax-sep 5196  ax-nul 5203  ax-pr 5322

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-3an 1085  df-tru 1536  df-ex 1777  df-nf 1781  df-sb 2066  df-mo 2618  df-eu 2650  df-clab 2800  df-cleq 2814  df-clel 2893  df-nfc 2963  df-ne 3017  df-ral 3143  df-rex 3144  df-rab 3147  df-v 3497  df-dif 3939  df-un 3941  df-in 3943  df-ss 3952  df-nul 4292  df-if 4468  df-sn 4562  df-pr 4564  df-op 4568  df-br 5060  df-opab 5122  df-xp 5556  df-rel 5557  df-cnv 5558  df-dm 5560  df-rn 5561  df-res 5562  df-ima 5563  df-bj-sngl 34273  df-bj-tag 34282  df-bj-proj 34298  df-bj-1upl 34305  df-bj-pr1 34308

This theorem is referenced by:  bj-1uplth  34314  bj-1uplex  34315  bj-pr21val  34320