Theorem islring 13925

Description: The predicate "is a local ring". (Contributed by SN, 23-Feb-2025.)

Hypotheses

Ref	Expression
islring.b	|- B = ( Base ` R )
islring.a	|- .+ = ( +g ` R )
islring.1	|- .1. = ( 1r ` R )
islring.u	|- U = (Unit ` R )

Assertion

Ref	Expression
islring	|- ( R e. LRing <-> ( R e. NzRing /\ A. x e. B A. y e. B ( ( x .+ y ) = .1. -> ( x e. U \/ y e. U ) ) ) )

Distinct variable groups:   x, R, y   x, B, y

Allowed substitution hints:   .+ ( x, y)   U( x, y)   .1. ( x, y)

Proof of Theorem islring

Dummy variable r is distinct from all other variables.

Step	Hyp	Ref	Expression
1		fveq2 5575	. . . 4 |- ( r = R -> ( Base ` r ) = ( Base ` R ) )
2		islring.b	. . . 4 |- B = ( Base ` R )
3	1, 2	eqtr4di 2255	. . 3 |- ( r = R -> ( Base ` r ) = B )
4		fveq2 5575	. . . . . . . 8 |- ( r = R -> ( +g ` r ) = ( +g ` R ) )
5		islring.a	. . . . . . . 8 |- .+ = ( +g ` R )
6	4, 5	eqtr4di 2255	. . . . . . 7 |- ( r = R -> ( +g ` r ) = .+ )
7	6	oveqd 5960	. . . . . 6 |- ( r = R -> ( x ( +g ` r ) y ) = ( x .+ y ) )
8		fveq2 5575	. . . . . . 7 |- ( r = R -> ( 1r ` r ) = ( 1r ` R ) )
9		islring.1	. . . . . . 7 |- .1. = ( 1r ` R )
10	8, 9	eqtr4di 2255	. . . . . 6 |- ( r = R -> ( 1r ` r ) = .1. )
11	7, 10	eqeq12d 2219	. . . . 5 |- ( r = R -> ( ( x ( +g ` r ) y ) = ( 1r ` r ) <-> ( x .+ y ) = .1. ) )
12		fveq2 5575	. . . . . . . 8 |- ( r = R -> (Unit ` r ) = (Unit ` R ) )
13		islring.u	. . . . . . . 8 |- U = (Unit ` R )
14	12, 13	eqtr4di 2255	. . . . . . 7 |- ( r = R -> (Unit ` r ) = U )
15	14	eleq2d 2274	. . . . . 6 |- ( r = R -> ( x e. (Unit ` r ) <-> x e. U ) )
16	14	eleq2d 2274	. . . . . 6 |- ( r = R -> ( y e. (Unit ` r ) <-> y e. U ) )
17	15, 16	orbi12d 794	. . . . 5 |- ( r = R -> ( ( x e. (Unit ` r ) \/ y e. (Unit ` r ) ) <-> ( x e. U \/ y e. U ) ) )
18	11, 17	imbi12d 234	. . . 4 |- ( r = R -> ( ( ( x ( +g ` r ) y ) = ( 1r ` r ) -> ( x e. (Unit ` r ) \/ y e. (Unit ` r ) ) ) <-> ( ( x .+ y ) = .1. -> ( x e. U \/ y e. U ) ) ) )
19	3, 18	raleqbidv 2717	. . 3 |- ( r = R -> ( A. y e. ( Base ` r ) ( ( x ( +g ` r ) y ) = ( 1r ` r ) -> ( x e. (Unit ` r ) \/ y e. (Unit ` r ) ) ) <-> A. y e. B ( ( x .+ y ) = .1. -> ( x e. U \/ y e. U ) ) ) )
20	3, 19	raleqbidv 2717	. 2 |- ( r = R -> ( A. x e. ( Base ` r ) A. y e. ( Base ` r ) ( ( x ( +g ` r ) y ) = ( 1r ` r ) -> ( x e. (Unit ` r ) \/ y e. (Unit ` r ) ) ) <-> A. x e. B A. y e. B ( ( x .+ y ) = .1. -> ( x e. U \/ y e. U ) ) ) )
21		df-lring 13924	. 2 |- LRing = { r e. NzRing | A. x e. ( Base ` r ) A. y e. ( Base ` r ) ( ( x ( +g ` r ) y ) = ( 1r ` r ) -> ( x e. (Unit ` r ) \/ y e. (Unit ` r ) ) ) }
22	20, 21	elrab2 2931	1 |- ( R e. LRing <-> ( R e. NzRing /\ A. x e. B A. y e. B ( ( x .+ y ) = .1. -> ( x e. U \/ y e. U ) ) ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   \/ wo 709   = wceq 1372   e. wcel 2175   A.wral 2483   ` cfv 5270  (class class class)co 5943   Basecbs 12803   +g cplusg 12880   1rcur 13692  Unitcui 13820  NzRingcnzr 13912  LRingclring 13923

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1469  ax-7 1470  ax-gen 1471  ax-ie1 1515  ax-ie2 1516  ax-8 1526  ax-10 1527  ax-11 1528  ax-i12 1529  ax-bndl 1531  ax-4 1532  ax-17 1548  ax-i9 1552  ax-ial 1556  ax-i5r 1557  ax-ext 2186

This theorem depends on definitions:  df-bi 117  df-3an 982  df-tru 1375  df-nf 1483  df-sb 1785  df-clab 2191  df-cleq 2197  df-clel 2200  df-nfc 2336  df-ral 2488  df-rex 2489  df-rab 2492  df-v 2773  df-un 3169  df-sn 3638  df-pr 3639  df-op 3641  df-uni 3850  df-br 4044  df-iota 5231  df-fv 5278  df-ov 5946  df-lring 13924

This theorem is referenced by:  lringuplu  13929