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Description: Obsolete version of isdrngd as of 19-Feb-2025. (Contributed by NM, 2-Aug-2013) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | isdrngdOLD.b | ⊢ ( 𝜑 → 𝐵 = ( Base ‘ 𝑅 ) ) | |
| isdrngdOLD.t | ⊢ ( 𝜑 → · = ( .r ‘ 𝑅 ) ) | ||
| isdrngdOLD.z | ⊢ ( 𝜑 → 0 = ( 0g ‘ 𝑅 ) ) | ||
| isdrngdOLD.u | ⊢ ( 𝜑 → 1 = ( 1r ‘ 𝑅 ) ) | ||
| isdrngdOLD.r | ⊢ ( 𝜑 → 𝑅 ∈ Ring ) | ||
| isdrngdOLD.n | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ ( 𝑦 ∈ 𝐵 ∧ 𝑦 ≠ 0 ) ) → ( 𝑥 · 𝑦 ) ≠ 0 ) | ||
| isdrngdOLD.o | ⊢ ( 𝜑 → 1 ≠ 0 ) | ||
| isdrngdOLD.i | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → 𝐼 ∈ 𝐵 ) | ||
| isdrngdOLD.j | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → 𝐼 ≠ 0 ) | ||
| isdrngdOLD.k | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → ( 𝐼 · 𝑥 ) = 1 ) | ||
| Assertion | isdrngdOLD | ⊢ ( 𝜑 → 𝑅 ∈ DivRing ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | isdrngdOLD.b | ⊢ ( 𝜑 → 𝐵 = ( Base ‘ 𝑅 ) ) | |
| 2 | isdrngdOLD.t | ⊢ ( 𝜑 → · = ( .r ‘ 𝑅 ) ) | |
| 3 | isdrngdOLD.z | ⊢ ( 𝜑 → 0 = ( 0g ‘ 𝑅 ) ) | |
| 4 | isdrngdOLD.u | ⊢ ( 𝜑 → 1 = ( 1r ‘ 𝑅 ) ) | |
| 5 | isdrngdOLD.r | ⊢ ( 𝜑 → 𝑅 ∈ Ring ) | |
| 6 | isdrngdOLD.n | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ ( 𝑦 ∈ 𝐵 ∧ 𝑦 ≠ 0 ) ) → ( 𝑥 · 𝑦 ) ≠ 0 ) | |
| 7 | isdrngdOLD.o | ⊢ ( 𝜑 → 1 ≠ 0 ) | |
| 8 | isdrngdOLD.i | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → 𝐼 ∈ 𝐵 ) | |
| 9 | isdrngdOLD.j | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → 𝐼 ≠ 0 ) | |
| 10 | isdrngdOLD.k | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → ( 𝐼 · 𝑥 ) = 1 ) | |
| 11 | difss | ⊢ ( 𝐵 ∖ { 0 } ) ⊆ 𝐵 | |
| 12 | 11 1 | sseqtrid | ⊢ ( 𝜑 → ( 𝐵 ∖ { 0 } ) ⊆ ( Base ‘ 𝑅 ) ) |
| 13 | eqid | ⊢ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) = ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) | |
| 14 | eqid | ⊢ ( mulGrp ‘ 𝑅 ) = ( mulGrp ‘ 𝑅 ) | |
| 15 | eqid | ⊢ ( Base ‘ 𝑅 ) = ( Base ‘ 𝑅 ) | |
| 16 | 14 15 | mgpbas | ⊢ ( Base ‘ 𝑅 ) = ( Base ‘ ( mulGrp ‘ 𝑅 ) ) |
| 17 | 13 16 | ressbas2 | ⊢ ( ( 𝐵 ∖ { 0 } ) ⊆ ( Base ‘ 𝑅 ) → ( 𝐵 ∖ { 0 } ) = ( Base ‘ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ) ) |
| 18 | 12 17 | syl | ⊢ ( 𝜑 → ( 𝐵 ∖ { 0 } ) = ( Base ‘ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ) ) |
| 19 | fvex | ⊢ ( Base ‘ 𝑅 ) ∈ V | |
| 20 | 1 19 | eqeltrdi | ⊢ ( 𝜑 → 𝐵 ∈ V ) |
| 21 | difexg | ⊢ ( 𝐵 ∈ V → ( 𝐵 ∖ { 0 } ) ∈ V ) | |
| 22 | eqid | ⊢ ( .r ‘ 𝑅 ) = ( .r ‘ 𝑅 ) | |
| 23 | 14 22 | mgpplusg | ⊢ ( .r ‘ 𝑅 ) = ( +g ‘ ( mulGrp ‘ 𝑅 ) ) |
| 24 | 13 23 | ressplusg | ⊢ ( ( 𝐵 ∖ { 0 } ) ∈ V → ( .r ‘ 𝑅 ) = ( +g ‘ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ) ) |
| 25 | 20 21 24 | 3syl | ⊢ ( 𝜑 → ( .r ‘ 𝑅 ) = ( +g ‘ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ) ) |
| 26 | 2 25 | eqtrd | ⊢ ( 𝜑 → · = ( +g ‘ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ) ) |
| 27 | eldifsn | ⊢ ( 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ↔ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) | |
| 28 | eldifsn | ⊢ ( 𝑦 ∈ ( 𝐵 ∖ { 0 } ) ↔ ( 𝑦 ∈ 𝐵 ∧ 𝑦 ≠ 0 ) ) | |
| 29 | 15 22 | ringcl | ⊢ ( ( 𝑅 ∈ Ring ∧ 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ) → ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ∈ ( Base ‘ 𝑅 ) ) |
| 30 | 5 29 | syl3an1 | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ) → ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ∈ ( Base ‘ 𝑅 ) ) |
| 31 | 30 | 3expib | ⊢ ( 𝜑 → ( ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ) → ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ∈ ( Base ‘ 𝑅 ) ) ) |
| 32 | 1 | eleq2d | ⊢ ( 𝜑 → ( 𝑥 ∈ 𝐵 ↔ 𝑥 ∈ ( Base ‘ 𝑅 ) ) ) |
| 33 | 1 | eleq2d | ⊢ ( 𝜑 → ( 𝑦 ∈ 𝐵 ↔ 𝑦 ∈ ( Base ‘ 𝑅 ) ) ) |
| 34 | 32 33 | anbi12d | ⊢ ( 𝜑 → ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ) ↔ ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ) ) ) |
| 35 | 2 | oveqd | ⊢ ( 𝜑 → ( 𝑥 · 𝑦 ) = ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ) |
| 36 | 35 1 | eleq12d | ⊢ ( 𝜑 → ( ( 𝑥 · 𝑦 ) ∈ 𝐵 ↔ ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ∈ ( Base ‘ 𝑅 ) ) ) |
| 37 | 31 34 36 | 3imtr4d | ⊢ ( 𝜑 → ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ) → ( 𝑥 · 𝑦 ) ∈ 𝐵 ) ) |
| 38 | 37 | 3impib | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ) → ( 𝑥 · 𝑦 ) ∈ 𝐵 ) |
| 39 | 38 | 3adant2r | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ 𝑦 ∈ 𝐵 ) → ( 𝑥 · 𝑦 ) ∈ 𝐵 ) |
| 40 | 39 | 3adant3r | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ ( 𝑦 ∈ 𝐵 ∧ 𝑦 ≠ 0 ) ) → ( 𝑥 · 𝑦 ) ∈ 𝐵 ) |
| 41 | eldifsn | ⊢ ( ( 𝑥 · 𝑦 ) ∈ ( 𝐵 ∖ { 0 } ) ↔ ( ( 𝑥 · 𝑦 ) ∈ 𝐵 ∧ ( 𝑥 · 𝑦 ) ≠ 0 ) ) | |
| 42 | 40 6 41 | sylanbrc | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ ( 𝑦 ∈ 𝐵 ∧ 𝑦 ≠ 0 ) ) → ( 𝑥 · 𝑦 ) ∈ ( 𝐵 ∖ { 0 } ) ) |
| 43 | 28 42 | syl3an3b | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ∧ 𝑦 ∈ ( 𝐵 ∖ { 0 } ) ) → ( 𝑥 · 𝑦 ) ∈ ( 𝐵 ∖ { 0 } ) ) |
| 44 | 27 43 | syl3an2b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ∧ 𝑦 ∈ ( 𝐵 ∖ { 0 } ) ) → ( 𝑥 · 𝑦 ) ∈ ( 𝐵 ∖ { 0 } ) ) |
| 45 | 15 22 | ringass | ⊢ ( ( 𝑅 ∈ Ring ∧ ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ∧ 𝑧 ∈ ( Base ‘ 𝑅 ) ) ) → ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) = ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) |
| 46 | 45 | ex | ⊢ ( 𝑅 ∈ Ring → ( ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ∧ 𝑧 ∈ ( Base ‘ 𝑅 ) ) → ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) = ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) |
| 47 | 5 46 | syl | ⊢ ( 𝜑 → ( ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ∧ 𝑧 ∈ ( Base ‘ 𝑅 ) ) → ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) = ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) |
| 48 | 1 | eleq2d | ⊢ ( 𝜑 → ( 𝑧 ∈ 𝐵 ↔ 𝑧 ∈ ( Base ‘ 𝑅 ) ) ) |
| 49 | 32 33 48 | 3anbi123d | ⊢ ( 𝜑 → ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) ↔ ( 𝑥 ∈ ( Base ‘ 𝑅 ) ∧ 𝑦 ∈ ( Base ‘ 𝑅 ) ∧ 𝑧 ∈ ( Base ‘ 𝑅 ) ) ) ) |
| 50 | eqidd | ⊢ ( 𝜑 → 𝑧 = 𝑧 ) | |
| 51 | 2 35 50 | oveq123d | ⊢ ( 𝜑 → ( ( 𝑥 · 𝑦 ) · 𝑧 ) = ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) ) |
| 52 | eqidd | ⊢ ( 𝜑 → 𝑥 = 𝑥 ) | |
| 53 | 2 | oveqd | ⊢ ( 𝜑 → ( 𝑦 · 𝑧 ) = ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) |
| 54 | 2 52 53 | oveq123d | ⊢ ( 𝜑 → ( 𝑥 · ( 𝑦 · 𝑧 ) ) = ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) |
| 55 | 51 54 | eqeq12d | ⊢ ( 𝜑 → ( ( ( 𝑥 · 𝑦 ) · 𝑧 ) = ( 𝑥 · ( 𝑦 · 𝑧 ) ) ↔ ( ( 𝑥 ( .r ‘ 𝑅 ) 𝑦 ) ( .r ‘ 𝑅 ) 𝑧 ) = ( 𝑥 ( .r ‘ 𝑅 ) ( 𝑦 ( .r ‘ 𝑅 ) 𝑧 ) ) ) ) |
| 56 | 47 49 55 | 3imtr4d | ⊢ ( 𝜑 → ( ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) → ( ( 𝑥 · 𝑦 ) · 𝑧 ) = ( 𝑥 · ( 𝑦 · 𝑧 ) ) ) ) |
| 57 | eldifi | ⊢ ( 𝑥 ∈ ( 𝐵 ∖ { 0 } ) → 𝑥 ∈ 𝐵 ) | |
| 58 | eldifi | ⊢ ( 𝑦 ∈ ( 𝐵 ∖ { 0 } ) → 𝑦 ∈ 𝐵 ) | |
| 59 | eldifi | ⊢ ( 𝑧 ∈ ( 𝐵 ∖ { 0 } ) → 𝑧 ∈ 𝐵 ) | |
| 60 | 57 58 59 | 3anim123i | ⊢ ( ( 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ∧ 𝑦 ∈ ( 𝐵 ∖ { 0 } ) ∧ 𝑧 ∈ ( 𝐵 ∖ { 0 } ) ) → ( 𝑥 ∈ 𝐵 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐵 ) ) |
| 61 | 56 60 | impel | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ∧ 𝑦 ∈ ( 𝐵 ∖ { 0 } ) ∧ 𝑧 ∈ ( 𝐵 ∖ { 0 } ) ) ) → ( ( 𝑥 · 𝑦 ) · 𝑧 ) = ( 𝑥 · ( 𝑦 · 𝑧 ) ) ) |
| 62 | eqid | ⊢ ( 1r ‘ 𝑅 ) = ( 1r ‘ 𝑅 ) | |
| 63 | 15 62 | ringidcl | ⊢ ( 𝑅 ∈ Ring → ( 1r ‘ 𝑅 ) ∈ ( Base ‘ 𝑅 ) ) |
| 64 | 5 63 | syl | ⊢ ( 𝜑 → ( 1r ‘ 𝑅 ) ∈ ( Base ‘ 𝑅 ) ) |
| 65 | 64 4 1 | 3eltr4d | ⊢ ( 𝜑 → 1 ∈ 𝐵 ) |
| 66 | eldifsn | ⊢ ( 1 ∈ ( 𝐵 ∖ { 0 } ) ↔ ( 1 ∈ 𝐵 ∧ 1 ≠ 0 ) ) | |
| 67 | 65 7 66 | sylanbrc | ⊢ ( 𝜑 → 1 ∈ ( 𝐵 ∖ { 0 } ) ) |
| 68 | 15 22 62 | ringlidm | ⊢ ( ( 𝑅 ∈ Ring ∧ 𝑥 ∈ ( Base ‘ 𝑅 ) ) → ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) = 𝑥 ) |
| 69 | 68 | ex | ⊢ ( 𝑅 ∈ Ring → ( 𝑥 ∈ ( Base ‘ 𝑅 ) → ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) = 𝑥 ) ) |
| 70 | 5 69 | syl | ⊢ ( 𝜑 → ( 𝑥 ∈ ( Base ‘ 𝑅 ) → ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) = 𝑥 ) ) |
| 71 | 2 4 52 | oveq123d | ⊢ ( 𝜑 → ( 1 · 𝑥 ) = ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) ) |
| 72 | 71 | eqeq1d | ⊢ ( 𝜑 → ( ( 1 · 𝑥 ) = 𝑥 ↔ ( ( 1r ‘ 𝑅 ) ( .r ‘ 𝑅 ) 𝑥 ) = 𝑥 ) ) |
| 73 | 70 32 72 | 3imtr4d | ⊢ ( 𝜑 → ( 𝑥 ∈ 𝐵 → ( 1 · 𝑥 ) = 𝑥 ) ) |
| 74 | 73 | imp | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐵 ) → ( 1 · 𝑥 ) = 𝑥 ) |
| 75 | 74 | adantrr | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → ( 1 · 𝑥 ) = 𝑥 ) |
| 76 | 27 75 | sylan2b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ) → ( 1 · 𝑥 ) = 𝑥 ) |
| 77 | eldifsn | ⊢ ( 𝐼 ∈ ( 𝐵 ∖ { 0 } ) ↔ ( 𝐼 ∈ 𝐵 ∧ 𝐼 ≠ 0 ) ) | |
| 78 | 8 9 77 | sylanbrc | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝐵 ∧ 𝑥 ≠ 0 ) ) → 𝐼 ∈ ( 𝐵 ∖ { 0 } ) ) |
| 79 | 27 78 | sylan2b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ) → 𝐼 ∈ ( 𝐵 ∖ { 0 } ) ) |
| 80 | 27 10 | sylan2b | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐵 ∖ { 0 } ) ) → ( 𝐼 · 𝑥 ) = 1 ) |
| 81 | 18 26 44 61 67 76 79 80 | isgrpd | ⊢ ( 𝜑 → ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ∈ Grp ) |
| 82 | 3 | sneqd | ⊢ ( 𝜑 → { 0 } = { ( 0g ‘ 𝑅 ) } ) |
| 83 | 1 82 | difeq12d | ⊢ ( 𝜑 → ( 𝐵 ∖ { 0 } ) = ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) |
| 84 | 83 | oveq2d | ⊢ ( 𝜑 → ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) = ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) ) |
| 85 | 84 | eleq1d | ⊢ ( 𝜑 → ( ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ∈ Grp ↔ ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) ∈ Grp ) ) |
| 86 | 85 | anbi2d | ⊢ ( 𝜑 → ( ( 𝑅 ∈ Ring ∧ ( ( mulGrp ‘ 𝑅 ) ↾s ( 𝐵 ∖ { 0 } ) ) ∈ Grp ) ↔ ( 𝑅 ∈ Ring ∧ ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) ∈ Grp ) ) ) |
| 87 | 5 81 86 | mpbi2and | ⊢ ( 𝜑 → ( 𝑅 ∈ Ring ∧ ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) ∈ Grp ) ) |
| 88 | eqid | ⊢ ( 0g ‘ 𝑅 ) = ( 0g ‘ 𝑅 ) | |
| 89 | eqid | ⊢ ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) = ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) | |
| 90 | 15 88 89 | isdrng2 | ⊢ ( 𝑅 ∈ DivRing ↔ ( 𝑅 ∈ Ring ∧ ( ( mulGrp ‘ 𝑅 ) ↾s ( ( Base ‘ 𝑅 ) ∖ { ( 0g ‘ 𝑅 ) } ) ) ∈ Grp ) ) |
| 91 | 87 90 | sylibr | ⊢ ( 𝜑 → 𝑅 ∈ DivRing ) |