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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | dfur2 20201* | The multiplicative identity is the unique element of the ring that is left- and right-neutral on all elements under multiplication. (Contributed by Mario Carneiro, 10-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ 1 = (℩𝑒(𝑒 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐵 ((𝑒 · 𝑥) = 𝑥 ∧ (𝑥 · 𝑒) = 𝑥))) | ||
Theorem | ringurd 20202* | Deduce the unity element of a ring from its properties. (Contributed by Thierry Arnoux, 6-Sep-2016.) |
⊢ (𝜑 → 𝐵 = (Base‘𝑅)) & ⊢ (𝜑 → · = (.r‘𝑅)) & ⊢ (𝜑 → 1 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ( 1 · 𝑥) = 𝑥) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → (𝑥 · 1 ) = 𝑥) ⇒ ⊢ (𝜑 → 1 = (1r‘𝑅)) | ||
Syntax | csrg 20203 | Extend class notation with the class of all semirings. |
class SRing | ||
Definition | df-srg 20204* | Define class of all semirings. A semiring is a set equipped with two everywhere-defined internal operations, whose first one is an additive commutative monoid structure and the second one is a multiplicative monoid structure, and where multiplication is (left- and right-) distributive over addition. Like with rings (df-ring 20252), the additive identity is an absorbing element of the multiplicative law, but in the case of semirings, this has to be part of the definition, as it cannot be deduced from distributivity alone. Definition of [Golan] p. 1. Note that our semirings are unital. Such semirings are sometimes called "rigs", being "rings without negatives". (Contributed by Thierry Arnoux, 21-Mar-2018.) |
⊢ SRing = {𝑓 ∈ CMnd ∣ ((mulGrp‘𝑓) ∈ Mnd ∧ [(Base‘𝑓) / 𝑟][(+g‘𝑓) / 𝑝][(.r‘𝑓) / 𝑡][(0g‘𝑓) / 𝑛]∀𝑥 ∈ 𝑟 (∀𝑦 ∈ 𝑟 ∀𝑧 ∈ 𝑟 ((𝑥𝑡(𝑦𝑝𝑧)) = ((𝑥𝑡𝑦)𝑝(𝑥𝑡𝑧)) ∧ ((𝑥𝑝𝑦)𝑡𝑧) = ((𝑥𝑡𝑧)𝑝(𝑦𝑡𝑧))) ∧ ((𝑛𝑡𝑥) = 𝑛 ∧ (𝑥𝑡𝑛) = 𝑛)))} | ||
Theorem | issrg 20205* | The predicate "is a semiring". (Contributed by Thierry Arnoux, 21-Mar-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 0 = (0g‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing ↔ (𝑅 ∈ CMnd ∧ 𝐺 ∈ Mnd ∧ ∀𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 ((𝑥 · (𝑦 + 𝑧)) = ((𝑥 · 𝑦) + (𝑥 · 𝑧)) ∧ ((𝑥 + 𝑦) · 𝑧) = ((𝑥 · 𝑧) + (𝑦 · 𝑧))) ∧ (( 0 · 𝑥) = 0 ∧ (𝑥 · 0 ) = 0 )))) | ||
Theorem | srgcmn 20206 | A semiring is a commutative monoid. (Contributed by Thierry Arnoux, 21-Mar-2018.) |
⊢ (𝑅 ∈ SRing → 𝑅 ∈ CMnd) | ||
Theorem | srgmnd 20207 | A semiring is a monoid. (Contributed by Thierry Arnoux, 21-Mar-2018.) |
⊢ (𝑅 ∈ SRing → 𝑅 ∈ Mnd) | ||
Theorem | srgmgp 20208 | A semiring is a monoid under multiplication. (Contributed by Thierry Arnoux, 21-Mar-2018.) |
⊢ 𝐺 = (mulGrp‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing → 𝐺 ∈ Mnd) | ||
Theorem | srgdilem 20209 | Lemma for srgdi 20214 and srgdir 20215. (Contributed by NM, 26-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 · (𝑌 + 𝑍)) = ((𝑋 · 𝑌) + (𝑋 · 𝑍)) ∧ ((𝑋 + 𝑌) · 𝑍) = ((𝑋 · 𝑍) + (𝑌 · 𝑍)))) | ||
Theorem | srgcl 20210 | Closure of the multiplication operation of a semiring. (Contributed by NM, 26-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 · 𝑌) ∈ 𝐵) | ||
Theorem | srgass 20211 | Associative law for the multiplication operation of a semiring. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 · 𝑌) · 𝑍) = (𝑋 · (𝑌 · 𝑍))) | ||
Theorem | srgideu 20212* | The unity element of a semiring is unique. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing → ∃!𝑢 ∈ 𝐵 ∀𝑥 ∈ 𝐵 ((𝑢 · 𝑥) = 𝑥 ∧ (𝑥 · 𝑢) = 𝑥)) | ||
Theorem | srgfcl 20213 | Functionality of the multiplication operation of a ring. (Contributed by Steve Rodriguez, 9-Sep-2007.) (Revised by AV, 24-Aug-2021.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ · Fn (𝐵 × 𝐵)) → · :(𝐵 × 𝐵)⟶𝐵) | ||
Theorem | srgdi 20214 | Distributive law for the multiplication operation of a semiring. (Contributed by Steve Rodriguez, 9-Sep-2007.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (𝑋 · (𝑌 + 𝑍)) = ((𝑋 · 𝑌) + (𝑋 · 𝑍))) | ||
Theorem | srgdir 20215 | Distributive law for the multiplication operation of a semiring. (Contributed by Steve Rodriguez, 9-Sep-2007.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 + 𝑌) · 𝑍) = ((𝑋 · 𝑍) + (𝑌 · 𝑍))) | ||
Theorem | srgidcl 20216 | The unity element of a semiring belongs to the base set of the semiring. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 27-Dec-2014.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing → 1 ∈ 𝐵) | ||
Theorem | srg0cl 20217 | The zero element of a semiring belongs to its base set. (Contributed by Mario Carneiro, 12-Jan-2014.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 0 = (0g‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing → 0 ∈ 𝐵) | ||
Theorem | srgidmlem 20218 | Lemma for srglidm 20219 and srgridm 20220. (Contributed by NM, 15-Sep-2011.) (Revised by Mario Carneiro, 27-Dec-2014.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → (( 1 · 𝑋) = 𝑋 ∧ (𝑋 · 1 ) = 𝑋)) | ||
Theorem | srglidm 20219 | The unity element of a semiring is a left multiplicative identity. (Contributed by NM, 15-Sep-2011.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → ( 1 · 𝑋) = 𝑋) | ||
Theorem | srgridm 20220 | The unity element of a semiring is a right multiplicative identity. (Contributed by NM, 15-Sep-2011.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → (𝑋 · 1 ) = 𝑋) | ||
Theorem | issrgid 20221* | Properties showing that an element 𝐼 is the unity element of a semiring. (Contributed by NM, 7-Aug-2013.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ (𝑅 ∈ SRing → ((𝐼 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐵 ((𝐼 · 𝑥) = 𝑥 ∧ (𝑥 · 𝐼) = 𝑥)) ↔ 1 = 𝐼)) | ||
Theorem | srgacl 20222 | Closure of the addition operation of a semiring. (Contributed by Mario Carneiro, 14-Jan-2014.) (Revised by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 + 𝑌) ∈ 𝐵) | ||
Theorem | srgcom 20223 | Commutativity of the additive group of a semiring. (Contributed by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 + 𝑌) = (𝑌 + 𝑋)) | ||
Theorem | srgrz 20224 | The zero of a semiring is a right-absorbing element. (Contributed by Thierry Arnoux, 1-Apr-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 0 = (0g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → (𝑋 · 0 ) = 0 ) | ||
Theorem | srglz 20225 | The zero of a semiring is a left-absorbing element. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 0 = (0g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → ( 0 · 𝑋) = 0 ) | ||
Theorem | srgisid 20226* | In a semiring, the only left-absorbing element is the additive identity. Remark in [Golan] p. 1. (Contributed by Thierry Arnoux, 1-May-2018.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 0 = (0g‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → (𝑍 · 𝑥) = 𝑍) ⇒ ⊢ (𝜑 → 𝑍 = 0 ) | ||
Theorem | o2timesd 20227* | An element of a ring-like structure plus itself is two times the element. "Two" in such a structure is the sum of the unity element with itself. This (formerly) part of the proof for ringcom 20293 depends on the (right) distributivity and the existence of a (left) multiplicative identity only. (Contributed by Gérard Lang, 4-Dec-2014.) (Revised by AV, 1-Feb-2025.) |
⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 ((𝑥 + 𝑦) · 𝑧) = ((𝑥 · 𝑧) + (𝑦 · 𝑧))) & ⊢ (𝜑 → 1 ∈ 𝐵) & ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ( 1 · 𝑥) = 𝑥) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑋 + 𝑋) = (( 1 + 1 ) · 𝑋)) | ||
Theorem | rglcom4d 20228* | Restricted commutativity of the addition in a ring-like structure. This (formerly) part of the proof for ringcom 20293 depends on the closure of the addition, the (left and right) distributivity and the existence of a (left) multiplicative identity only. (Contributed by Gérard Lang, 4-Dec-2014.) (Revised by AV, 1-Feb-2025.) |
⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 ((𝑥 + 𝑦) · 𝑧) = ((𝑥 · 𝑧) + (𝑦 · 𝑧))) & ⊢ (𝜑 → 1 ∈ 𝐵) & ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ( 1 · 𝑥) = 𝑥) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 (𝑥 + 𝑦) ∈ 𝐵) & ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 (𝑥 · (𝑦 + 𝑧)) = ((𝑥 · 𝑦) + (𝑥 · 𝑧))) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) ⇒ ⊢ (𝜑 → ((𝑋 + 𝑋) + (𝑌 + 𝑌)) = ((𝑋 + 𝑌) + (𝑋 + 𝑌))) | ||
Theorem | srgo2times 20229 | A semiring element plus itself is two times the element. "Two" in an arbitrary (unital) semiring is the sum of the unity element with itself. (Contributed by AV, 24-Aug-2021.) Variant of o2timesd 20227 for semirings. (Revised by AV, 1-Feb-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝐴 ∈ 𝐵) → (𝐴 + 𝐴) = (( 1 + 1 ) · 𝐴)) | ||
Theorem | srgcom4lem 20230 | Lemma for srgcom4 20231. This (formerly) part of the proof for ringcom 20293 is applicable for semirings (without using the commutativity of the addition given per definition of a semiring). (Contributed by Gérard Lang, 4-Dec-2014.) (Revised by AV, 1-Feb-2025.) (Proof modification is discouraged.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → ((𝑋 + 𝑋) + (𝑌 + 𝑌)) = ((𝑋 + 𝑌) + (𝑋 + 𝑌))) | ||
Theorem | srgcom4 20231 | Restricted commutativity of the addition in semirings (without using the commutativity of the addition given per definition of a semiring). (Contributed by AV, 1-Feb-2025.) (Proof modification is discouraged.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → ((𝑋 + (𝑋 + 𝑌)) + 𝑌) = ((𝑋 + (𝑌 + 𝑋)) + 𝑌)) | ||
Theorem | srg1zr 20232 | The only semiring with a base set consisting of one element is the zero ring (at least if its operations are internal binary operations). (Contributed by FL, 13-Feb-2010.) (Revised by AV, 25-Jan-2020.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ ∗ = (.r‘𝑅) ⇒ ⊢ (((𝑅 ∈ SRing ∧ + Fn (𝐵 × 𝐵) ∧ ∗ Fn (𝐵 × 𝐵)) ∧ 𝑍 ∈ 𝐵) → (𝐵 = {𝑍} ↔ ( + = {〈〈𝑍, 𝑍〉, 𝑍〉} ∧ ∗ = {〈〈𝑍, 𝑍〉, 𝑍〉}))) | ||
Theorem | srgen1zr 20233 | The only semiring with one element is the zero ring (at least if its operations are internal binary operations). (Contributed by FL, 14-Feb-2010.) (Revised by AV, 25-Jan-2020.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ ∗ = (.r‘𝑅) & ⊢ 𝑍 = (0g‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ + Fn (𝐵 × 𝐵) ∧ ∗ Fn (𝐵 × 𝐵)) → (𝐵 ≈ 1o ↔ ( + = {〈〈𝑍, 𝑍〉, 𝑍〉} ∧ ∗ = {〈〈𝑍, 𝑍〉, 𝑍〉}))) | ||
Theorem | srgmulgass 20234 | An associative property between group multiple and ring multiplication for semirings. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ × = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ (𝑁 ∈ ℕ0 ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵)) → ((𝑁 · 𝑋) × 𝑌) = (𝑁 · (𝑋 × 𝑌))) | ||
Theorem | srgpcomp 20235 | If two elements of a semiring commute, they also commute if one of the elements is raised to a higher power. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐾 ∈ ℕ0) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) ⇒ ⊢ (𝜑 → ((𝐾 ↑ 𝐵) × 𝐴) = (𝐴 × (𝐾 ↑ 𝐵))) | ||
Theorem | srgpcompp 20236 | If two elements of a semiring commute, they also commute if the elements are raised to a higher power. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐾 ∈ ℕ0) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) ⇒ ⊢ (𝜑 → (((𝑁 ↑ 𝐴) × (𝐾 ↑ 𝐵)) × 𝐴) = (((𝑁 + 1) ↑ 𝐴) × (𝐾 ↑ 𝐵))) | ||
Theorem | srgpcomppsc 20237 | If two elements of a semiring commute, they also commute if the elements are raised to a higher power and a scalar multiplication is involved. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐾 ∈ ℕ0) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ · = (.g‘𝑅) & ⊢ (𝜑 → 𝐶 ∈ ℕ0) ⇒ ⊢ (𝜑 → ((𝐶 · ((𝑁 ↑ 𝐴) × (𝐾 ↑ 𝐵))) × 𝐴) = (𝐶 · (((𝑁 + 1) ↑ 𝐴) × (𝐾 ↑ 𝐵)))) | ||
Theorem | srglmhm 20238* | Left-multiplication in a semiring by a fixed element of the ring is a monoid homomorphism, analogous to ringlghm 20325. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → (𝑥 ∈ 𝐵 ↦ (𝑋 · 𝑥)) ∈ (𝑅 MndHom 𝑅)) | ||
Theorem | srgrmhm 20239* | Right-multiplication in a semiring by a fixed element of the ring is a monoid homomorphism, analogous to ringrghm 20326. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑋 ∈ 𝐵) → (𝑥 ∈ 𝐵 ↦ (𝑥 · 𝑋)) ∈ (𝑅 MndHom 𝑅)) | ||
Theorem | srgsummulcr 20240* | A finite semiring sum multiplied by a constant, analogous to gsummulc1 20329. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 0 = (0g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ 𝑋) finSupp 0 ) ⇒ ⊢ (𝜑 → (𝑅 Σg (𝑘 ∈ 𝐴 ↦ (𝑋 · 𝑌))) = ((𝑅 Σg (𝑘 ∈ 𝐴 ↦ 𝑋)) · 𝑌)) | ||
Theorem | sgsummulcl 20241* | A finite semiring sum multiplied by a constant, analogous to gsummulc2 20330. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 0 = (0g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ 𝑋) finSupp 0 ) ⇒ ⊢ (𝜑 → (𝑅 Σg (𝑘 ∈ 𝐴 ↦ (𝑌 · 𝑋))) = (𝑌 · (𝑅 Σg (𝑘 ∈ 𝐴 ↦ 𝑋)))) | ||
Theorem | srg1expzeq1 20242 | The exponentiation (by a nonnegative integer) of the multiplicative identity of a semiring, analogous to mulgnn0z 19131. (Contributed by AV, 25-Nov-2019.) |
⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ · = (.g‘𝐺) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ SRing ∧ 𝑁 ∈ ℕ0) → (𝑁 · 1 ) = 1 ) | ||
In this section, we prove the binomial theorem for semirings, srgbinom 20248, which is a generalization of the binomial theorem for complex numbers, binom 15862: (𝐴 + 𝐵)↑𝑁 is the sum from 𝑘 = 0 to 𝑁 of (𝑁C𝑘) · ((𝐴↑𝑘) · (𝐵↑(𝑁 − 𝑘)). Note that the binomial theorem also holds in the non-unital case (that is, in a "rg") and actually, the additive identity is not needed in its proof either. Therefore, it can be proven in even more general cases. An example is the "rg" (resp. "rg without a zero") of integrable nonnegative (resp. positive) functions on ℝ. Special cases of the binomial theorem are csrgbinom 20249 (binomial theorem for commutative semirings) and crngbinom 20348 (binomial theorem for commutative rings). | ||
Theorem | srgbinomlem1 20243 | Lemma 1 for srgbinomlem 20247. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) ⇒ ⊢ ((𝜑 ∧ (𝐷 ∈ ℕ0 ∧ 𝐸 ∈ ℕ0)) → ((𝐷 ↑ 𝐴) × (𝐸 ↑ 𝐵)) ∈ 𝑆) | ||
Theorem | srgbinomlem2 20244 | Lemma 2 for srgbinomlem 20247. (Contributed by AV, 23-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) ⇒ ⊢ ((𝜑 ∧ (𝐶 ∈ ℕ0 ∧ 𝐷 ∈ ℕ0 ∧ 𝐸 ∈ ℕ0)) → (𝐶 · ((𝐷 ↑ 𝐴) × (𝐸 ↑ 𝐵))) ∈ 𝑆) | ||
Theorem | srgbinomlem3 20245* | Lemma 3 for srgbinomlem 20247. (Contributed by AV, 23-Aug-2019.) (Proof shortened by AV, 27-Oct-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ (𝜓 → (𝑁 ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...𝑁) ↦ ((𝑁C𝑘) · (((𝑁 − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) ⇒ ⊢ ((𝜑 ∧ 𝜓) → ((𝑁 ↑ (𝐴 + 𝐵)) × 𝐴) = (𝑅 Σg (𝑘 ∈ (0...(𝑁 + 1)) ↦ ((𝑁C𝑘) · ((((𝑁 + 1) − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) | ||
Theorem | srgbinomlem4 20246* | Lemma 4 for srgbinomlem 20247. (Contributed by AV, 24-Aug-2019.) (Proof shortened by AV, 19-Nov-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ (𝜓 → (𝑁 ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...𝑁) ↦ ((𝑁C𝑘) · (((𝑁 − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) ⇒ ⊢ ((𝜑 ∧ 𝜓) → ((𝑁 ↑ (𝐴 + 𝐵)) × 𝐵) = (𝑅 Σg (𝑘 ∈ (0...(𝑁 + 1)) ↦ ((𝑁C(𝑘 − 1)) · ((((𝑁 + 1) − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) | ||
Theorem | srgbinomlem 20247* | Lemma for srgbinom 20248. Inductive step, analogous to binomlem 15861. (Contributed by AV, 24-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) & ⊢ (𝜑 → 𝑅 ∈ SRing) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → (𝐴 × 𝐵) = (𝐵 × 𝐴)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ (𝜓 → (𝑁 ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...𝑁) ↦ ((𝑁C𝑘) · (((𝑁 − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) ⇒ ⊢ ((𝜑 ∧ 𝜓) → ((𝑁 + 1) ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...(𝑁 + 1)) ↦ (((𝑁 + 1)C𝑘) · ((((𝑁 + 1) − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) | ||
Theorem | srgbinom 20248* | The binomial theorem for commuting elements of a semiring: (𝐴 + 𝐵)↑𝑁 is the sum from 𝑘 = 0 to 𝑁 of (𝑁C𝑘) · ((𝐴↑𝑘) · (𝐵↑(𝑁 − 𝑘)) (generalization of binom 15862). (Contributed by AV, 24-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) ⇒ ⊢ (((𝑅 ∈ SRing ∧ 𝑁 ∈ ℕ0) ∧ (𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆 ∧ (𝐴 × 𝐵) = (𝐵 × 𝐴))) → (𝑁 ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...𝑁) ↦ ((𝑁C𝑘) · (((𝑁 − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) | ||
Theorem | csrgbinom 20249* | The binomial theorem for commutative semirings. (Contributed by AV, 24-Aug-2019.) |
⊢ 𝑆 = (Base‘𝑅) & ⊢ × = (.r‘𝑅) & ⊢ · = (.g‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ ↑ = (.g‘𝐺) ⇒ ⊢ (((𝑅 ∈ SRing ∧ 𝐺 ∈ CMnd ∧ 𝑁 ∈ ℕ0) ∧ (𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆)) → (𝑁 ↑ (𝐴 + 𝐵)) = (𝑅 Σg (𝑘 ∈ (0...𝑁) ↦ ((𝑁C𝑘) · (((𝑁 − 𝑘) ↑ 𝐴) × (𝑘 ↑ 𝐵)))))) | ||
Syntax | crg 20250 | Extend class notation with class of all (unital) rings. |
class Ring | ||
Syntax | ccrg 20251 | Extend class notation with class of all (unital) commutative rings. |
class CRing | ||
Definition | df-ring 20252* | Define class of all (unital) rings. A unital ring is a set equipped with two everywhere-defined internal operations, whose first one is an additive group structure and the second one is a multiplicative monoid structure, and where the addition is left- and right-distributive for the multiplication. Definition 1 in [BourbakiAlg1] p. 92 or definition of a ring with identity in part Preliminaries of [Roman] p. 19. So that the additive structure must be abelian (see ringcom 20293), care must be taken that in the case of a non-unital ring, the commutativity of addition must be postulated and cannot be proved from the other conditions. Therefore, it can be shown that a unital ring is a non-unital ring (ringrng 20298) only after ringabl 20294 was proven. (Contributed by NM, 18-Oct-2012.) (Revised by Mario Carneiro, 27-Dec-2014.) |
⊢ Ring = {𝑓 ∈ Grp ∣ ((mulGrp‘𝑓) ∈ Mnd ∧ [(Base‘𝑓) / 𝑟][(+g‘𝑓) / 𝑝][(.r‘𝑓) / 𝑡]∀𝑥 ∈ 𝑟 ∀𝑦 ∈ 𝑟 ∀𝑧 ∈ 𝑟 ((𝑥𝑡(𝑦𝑝𝑧)) = ((𝑥𝑡𝑦)𝑝(𝑥𝑡𝑧)) ∧ ((𝑥𝑝𝑦)𝑡𝑧) = ((𝑥𝑡𝑧)𝑝(𝑦𝑡𝑧))))} | ||
Definition | df-cring 20253 | Define class of all commutative rings. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ CRing = {𝑓 ∈ Ring ∣ (mulGrp‘𝑓) ∈ CMnd} | ||
Theorem | isring 20254* | The predicate "is a (unital) ring". Definition of "ring with unit" in [Schechter] p. 187. (Contributed by NM, 18-Oct-2012.) (Revised by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 𝐺 = (mulGrp‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring ↔ (𝑅 ∈ Grp ∧ 𝐺 ∈ Mnd ∧ ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ∀𝑧 ∈ 𝐵 ((𝑥 · (𝑦 + 𝑧)) = ((𝑥 · 𝑦) + (𝑥 · 𝑧)) ∧ ((𝑥 + 𝑦) · 𝑧) = ((𝑥 · 𝑧) + (𝑦 · 𝑧))))) | ||
Theorem | ringgrp 20255 | A ring is a group. (Contributed by NM, 15-Sep-2011.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Grp) | ||
Theorem | ringmgp 20256 | A ring is a monoid under multiplication. (Contributed by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐺 = (mulGrp‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring → 𝐺 ∈ Mnd) | ||
Theorem | iscrng 20257 | A commutative ring is a ring whose multiplication is a commutative monoid. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ 𝐺 = (mulGrp‘𝑅) ⇒ ⊢ (𝑅 ∈ CRing ↔ (𝑅 ∈ Ring ∧ 𝐺 ∈ CMnd)) | ||
Theorem | crngmgp 20258 | A commutative ring's multiplication operation is commutative. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ 𝐺 = (mulGrp‘𝑅) ⇒ ⊢ (𝑅 ∈ CRing → 𝐺 ∈ CMnd) | ||
Theorem | ringgrpd 20259 | A ring is a group. (Contributed by SN, 16-May-2024.) |
⊢ (𝜑 → 𝑅 ∈ Ring) ⇒ ⊢ (𝜑 → 𝑅 ∈ Grp) | ||
Theorem | ringmnd 20260 | A ring is a monoid under addition. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Mnd) | ||
Theorem | ringmgm 20261 | A ring is a magma. (Contributed by AV, 31-Jan-2020.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Mgm) | ||
Theorem | crngring 20262 | A commutative ring is a ring. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ (𝑅 ∈ CRing → 𝑅 ∈ Ring) | ||
Theorem | crngringd 20263 | A commutative ring is a ring. (Contributed by SN, 16-May-2024.) |
⊢ (𝜑 → 𝑅 ∈ CRing) ⇒ ⊢ (𝜑 → 𝑅 ∈ Ring) | ||
Theorem | crnggrpd 20264 | A commutative ring is a group. (Contributed by SN, 16-May-2024.) |
⊢ (𝜑 → 𝑅 ∈ CRing) ⇒ ⊢ (𝜑 → 𝑅 ∈ Grp) | ||
Theorem | mgpf 20265 | Restricted functionality of the multiplicative group on rings. (Contributed by Mario Carneiro, 11-Mar-2015.) |
⊢ (mulGrp ↾ Ring):Ring⟶Mnd | ||
Theorem | ringdilem 20266 | Properties of a unital ring. (Contributed by NM, 26-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 · (𝑌 + 𝑍)) = ((𝑋 · 𝑌) + (𝑋 · 𝑍)) ∧ ((𝑋 + 𝑌) · 𝑍) = ((𝑋 · 𝑍) + (𝑌 · 𝑍)))) | ||
Theorem | ringcl 20267 | Closure of the multiplication operation of a ring. (Contributed by NM, 26-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 · 𝑌) ∈ 𝐵) | ||
Theorem | crngcom 20268 | A commutative ring's multiplication operation is commutative. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ CRing ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 · 𝑌) = (𝑌 · 𝑋)) | ||
Theorem | iscrng2 20269* | A commutative ring is a ring whose multiplication is a commutative monoid. (Contributed by Mario Carneiro, 15-Jun-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ (𝑅 ∈ CRing ↔ (𝑅 ∈ Ring ∧ ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 (𝑥 · 𝑦) = (𝑦 · 𝑥))) | ||
Theorem | ringass 20270 | Associative law for multiplication in a ring. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 · 𝑌) · 𝑍) = (𝑋 · (𝑌 · 𝑍))) | ||
Theorem | ringideu 20271* | The unity element of a ring is unique. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 6-Jan-2015.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring → ∃!𝑢 ∈ 𝐵 ∀𝑥 ∈ 𝐵 ((𝑢 · 𝑥) = 𝑥 ∧ (𝑥 · 𝑢) = 𝑥)) | ||
Theorem | crngcomd 20272 | Multiplication is commutative in a commutative ring. (Contributed by SN, 8-Mar-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ CRing) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑋 · 𝑌) = (𝑌 · 𝑋)) | ||
Theorem | crngbascntr 20273 | The base set of a commutative ring is its center. (Contributed by SN, 21-Mar-2025.) |
⊢ 𝐵 = (Base‘𝐺) & ⊢ 𝑍 = (Cntr‘(mulGrp‘𝐺)) ⇒ ⊢ (𝐺 ∈ CRing → 𝐵 = 𝑍) | ||
Theorem | ringassd 20274 | Associative law for multiplication in a ring. (Contributed by SN, 14-Aug-2024.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ Ring) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ (𝜑 → ((𝑋 · 𝑌) · 𝑍) = (𝑋 · (𝑌 · 𝑍))) | ||
Theorem | crng12d 20275 | Commutative/associative law that swaps the first two factors in a triple product. (Contributed by SN, 8-Mar-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ CRing) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑋 · (𝑌 · 𝑍)) = (𝑌 · (𝑋 · 𝑍))) | ||
Theorem | ringcld 20276 | Closure of the multiplication operation of a ring. (Contributed by SN, 29-Jul-2024.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ Ring) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑋 · 𝑌) ∈ 𝐵) | ||
Theorem | ringdi 20277 | Distributive law for the multiplication operation of a ring (left-distributivity). (Contributed by Steve Rodriguez, 9-Sep-2007.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → (𝑋 · (𝑌 + 𝑍)) = ((𝑋 · 𝑌) + (𝑋 · 𝑍))) | ||
Theorem | ringdir 20278 | Distributive law for the multiplication operation of a ring (right-distributivity). (Contributed by Steve Rodriguez, 9-Sep-2007.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ (𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵)) → ((𝑋 + 𝑌) · 𝑍) = ((𝑋 · 𝑍) + (𝑌 · 𝑍))) | ||
Theorem | ringidcl 20279 | The unity element of a ring belongs to the base set of the ring. (Contributed by NM, 27-Aug-2011.) (Revised by Mario Carneiro, 27-Dec-2014.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring → 1 ∈ 𝐵) | ||
Theorem | ring0cl 20280 | The zero element of a ring belongs to its base set. (Contributed by Mario Carneiro, 12-Jan-2014.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ 0 = (0g‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring → 0 ∈ 𝐵) | ||
Theorem | ringidmlem 20281 | Lemma for ringlidm 20282 and ringridm 20283. (Contributed by NM, 15-Sep-2011.) (Revised by Mario Carneiro, 27-Dec-2014.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵) → (( 1 · 𝑋) = 𝑋 ∧ (𝑋 · 1 ) = 𝑋)) | ||
Theorem | ringlidm 20282 | The unity element of a ring is a left multiplicative identity. (Contributed by NM, 15-Sep-2011.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵) → ( 1 · 𝑋) = 𝑋) | ||
Theorem | ringridm 20283 | The unity element of a ring is a right multiplicative identity. (Contributed by NM, 15-Sep-2011.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵) → (𝑋 · 1 ) = 𝑋) | ||
Theorem | isringid 20284* | Properties showing that an element 𝐼 is the unity element of a ring. (Contributed by NM, 7-Aug-2013.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring → ((𝐼 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐵 ((𝐼 · 𝑥) = 𝑥 ∧ (𝑥 · 𝐼) = 𝑥)) ↔ 1 = 𝐼)) | ||
Theorem | ringlidmd 20285 | The unity element of a ring is a left multiplicative identity. (Contributed by SN, 14-Aug-2024.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ Ring) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) ⇒ ⊢ (𝜑 → ( 1 · 𝑋) = 𝑋) | ||
Theorem | ringridmd 20286 | The unity element of a ring is a right multiplicative identity. (Contributed by SN, 14-Aug-2024.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ Ring) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑋 · 1 ) = 𝑋) | ||
Theorem | ringid 20287* | The multiplication operation of a unital ring has (one or more) identity elements. (Contributed by Steve Rodriguez, 9-Sep-2007.) (Revised by Mario Carneiro, 22-Dec-2013.) (Revised by AV, 24-Aug-2021.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵) → ∃𝑢 ∈ 𝐵 ((𝑢 · 𝑋) = 𝑋 ∧ (𝑋 · 𝑢) = 𝑋)) | ||
Theorem | ringo2times 20288 | A ring element plus itself is two times the element. "Two" in an arbitrary unital ring is the sum of the unity element with itself. (Contributed by AV, 24-Aug-2021.) Variant of o2timesd 20227 for rings. (Revised by AV, 5-Feb-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝐴 ∈ 𝐵) → (𝐴 + 𝐴) = (( 1 + 1 ) · 𝐴)) | ||
Theorem | ringadd2 20289* | A ring element plus itself is two times the element. (Contributed by Steve Rodriguez, 9-Sep-2007.) (Revised by Mario Carneiro, 22-Dec-2013.) (Revised by AV, 24-Aug-2021.) (Proof shortened by AV, 1-Feb-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵) → ∃𝑥 ∈ 𝐵 (𝑋 + 𝑋) = ((𝑥 + 𝑥) · 𝑋)) | ||
Theorem | ringidss 20290 | A subset of the multiplicative group has the multiplicative identity as its identity if the identity is in the subset. (Contributed by Mario Carneiro, 27-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝑀 = ((mulGrp‘𝑅) ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑅) & ⊢ 1 = (1r‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝐴 ⊆ 𝐵 ∧ 1 ∈ 𝐴) → 1 = (0g‘𝑀)) | ||
Theorem | ringacl 20291 | Closure of the addition operation of a ring. (Contributed by Mario Carneiro, 14-Jan-2014.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 + 𝑌) ∈ 𝐵) | ||
Theorem | ringcomlem 20292 | Lemma for ringcom 20293. This (formerly) part of the proof for ringcom 20293 is also applicable for semirings (without using the commutativity of the addition given per definition of a semiring), see srgcom4lem 20230. (Contributed by Gérard Lang, 4-Dec-2014.) Variant of rglcom4d 20228 for rings. (Revised by AV, 5-Feb-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → ((𝑋 + 𝑋) + (𝑌 + 𝑌)) = ((𝑋 + 𝑌) + (𝑋 + 𝑌))) | ||
Theorem | ringcom 20293 | Commutativity of the additive group of a ring. (See also lmodcom 20922.) This proof requires the existence of a multiplicative identity, and the existence of additive inverses. Therefore, this proof is not applicable for semirings. (Contributed by Gérard Lang, 4-Dec-2014.) (Proof shortened by AV, 1-Feb-2025.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ + = (+g‘𝑅) ⇒ ⊢ ((𝑅 ∈ Ring ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 + 𝑌) = (𝑌 + 𝑋)) | ||
Theorem | ringabl 20294 | A ring is an Abelian group. (Contributed by NM, 26-Aug-2011.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Abel) | ||
Theorem | ringcmn 20295 | A ring is a commutative monoid. (Contributed by Mario Carneiro, 7-Jan-2015.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ CMnd) | ||
Theorem | ringabld 20296 | A ring is an Abelian group. (Contributed by SN, 1-Jun-2024.) |
⊢ (𝜑 → 𝑅 ∈ Ring) ⇒ ⊢ (𝜑 → 𝑅 ∈ Abel) | ||
Theorem | ringcmnd 20297 | A ring is a commutative monoid. (Contributed by SN, 1-Jun-2024.) |
⊢ (𝜑 → 𝑅 ∈ Ring) ⇒ ⊢ (𝜑 → 𝑅 ∈ CMnd) | ||
Theorem | ringrng 20298 | A unital ring is a non-unital ring. (Contributed by AV, 6-Jan-2020.) |
⊢ (𝑅 ∈ Ring → 𝑅 ∈ Rng) | ||
Theorem | ringssrng 20299 | The unital rings are non-unital rings. (Contributed by AV, 20-Mar-2020.) |
⊢ Ring ⊆ Rng | ||
Theorem | isringrng 20300* | The predicate "is a unital ring" as extension of the predicate "is a non-unital ring". (Contributed by AV, 17-Feb-2020.) |
⊢ 𝐵 = (Base‘𝑅) & ⊢ · = (.r‘𝑅) ⇒ ⊢ (𝑅 ∈ Ring ↔ (𝑅 ∈ Rng ∧ ∃𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 ((𝑥 · 𝑦) = 𝑦 ∧ (𝑦 · 𝑥) = 𝑦))) |
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