Theorem ifcldadc 3378

Description: Conditional closure. (Contributed by Jim Kingdon, 11-Jan-2022.)

Hypotheses

Ref	Expression
ifcldadc.1	|- ( ( ph /\ ps ) -> A e. C )
ifcldadc.2	|- ( ( ph /\ -. ps ) -> B e. C )
ifcldadc.dc	|- ( ph -> DECID ps )

Assertion

Ref	Expression
ifcldadc	|- ( ph -> if ( ps , A , B ) e. C )

Proof of Theorem ifcldadc

Step	Hyp	Ref	Expression
1		iftrue 3356	. . . 4 |- ( ps -> if ( ps , A , B ) = A )
2	1	adantl 271	. . 3 |- ( ( ph /\ ps ) -> if ( ps , A , B ) = A )
3		ifcldadc.1	. . 3 |- ( ( ph /\ ps ) -> A e. C )
4	2, 3	eqeltrd 2155	. 2 |- ( ( ph /\ ps ) -> if ( ps , A , B ) e. C )
5		iffalse 3359	. . . 4 |- ( -. ps -> if ( ps , A , B ) = B )
6	5	adantl 271	. . 3 |- ( ( ph /\ -. ps ) -> if ( ps , A , B ) = B )
7		ifcldadc.2	. . 3 |- ( ( ph /\ -. ps ) -> B e. C )
8	6, 7	eqeltrd 2155	. 2 |- ( ( ph /\ -. ps ) -> if ( ps , A , B ) e. C )
9		ifcldadc.dc	. . 3 |- ( ph -> DECID ps )
10		exmiddc 777	. . 3 |- (DECID ps -> ( ps \/ -. ps ) )
11	9, 10	syl 14	. 2 |- ( ph -> ( ps \/ -. ps ) )
12	4, 8, 11	mpjaodan 744	1 |- ( ph -> if ( ps , A , B ) e. C )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 102   \/ wo 661  DECID wdc 775   = wceq 1284   e. wcel 1433   ifcif 3351

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in2 577  ax-io 662  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-dc 776  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-if 3352

This theorem is referenced by:  eucalgval2  10435  lcmval  10445