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Theorem srgisid 20188

Description: In a semiring, the only left-absorbing element is the additive identity. Remark in [Golan] p. 1. (Contributed by Thierry Arnoux, 1-May-2018.)

**Hypotheses**
Ref	Expression
srgz.b	⊢ 𝐵 = (Base‘𝑅)
srgz.t	⊢ · = (._r‘𝑅)
srgz.z	⊢ 0 = (0_g‘𝑅)
srgisid.1	⊢ (𝜑 → 𝑅 ∈ SRing)
srgisid.2	⊢ (𝜑 → 𝑍 ∈ 𝐵)
srgisid.3	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → (𝑍 · 𝑥) = 𝑍)

**Assertion**
Ref	Expression
srgisid	⊢ (𝜑 → 𝑍 = 0 )

Distinct variable groups: 𝑥,𝐵 𝑥,𝑅 𝑥, · 𝑥, 0 𝑥,𝑍 𝜑,𝑥

**Proof of Theorem srgisid**
Step	Hyp	Ref	Expression
1		srgisid.3	. . . 4 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → (𝑍 · 𝑥) = 𝑍)
2	1	ralrimiva 3132	. . 3 ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 (𝑍 · 𝑥) = 𝑍)
3		srgisid.1	. . . 4 ⊢ (𝜑 → 𝑅 ∈ SRing)
4		srgz.b	. . . . 5 ⊢ 𝐵 = (Base‘𝑅)
5		srgz.z	. . . . 5 ⊢ 0 = (0_g‘𝑅)
6	4, 5	srg0cl 20179	. . . 4 ⊢ (𝑅 ∈ SRing → 0 ∈ 𝐵)
7		oveq2 7371	. . . . . 6 ⊢ (𝑥 = 0 → (𝑍 · 𝑥) = (𝑍 · 0 ))
8	7	eqeq1d 2742	. . . . 5 ⊢ (𝑥 = 0 → ((𝑍 · 𝑥) = 𝑍 ↔ (𝑍 · 0 ) = 𝑍))
9	8	rspcv 3563	. . . 4 ⊢ ( 0 ∈ 𝐵 → (∀𝑥 ∈ 𝐵 (𝑍 · 𝑥) = 𝑍 → (𝑍 · 0 ) = 𝑍))
10	3, 6, 9	3syl 18	. . 3 ⊢ (𝜑 → (∀𝑥 ∈ 𝐵 (𝑍 · 𝑥) = 𝑍 → (𝑍 · 0 ) = 𝑍))
11	2, 10	mpd 15	. 2 ⊢ (𝜑 → (𝑍 · 0 ) = 𝑍)
12		srgisid.2	. . 3 ⊢ (𝜑 → 𝑍 ∈ 𝐵)
13		srgz.t	. . . 4 ⊢ · = (._r‘𝑅)
14	4, 13, 5	srgrz 20186	. . 3 ⊢ ((𝑅 ∈ SRing ∧ 𝑍 ∈ 𝐵) → (𝑍 · 0 ) = 0 )
15	3, 12, 14	syl2anc 590	. 2 ⊢ (𝜑 → (𝑍 · 0 ) = 0 )
16	11, 15	eqtr3d 2777	1 ⊢ (𝜑 → 𝑍 = 0 )

Colors of variables: wff setvar class

Syntax hints: → wi 4 ∧ wa 396 = wceq 1547 ∈ wcel 2119 ∀wral 3054 ‘cfv 6492 (class class class)co 7363 Basecbs 17177 ._rcmulr 17219 0_gc0g 17400 SRingcsrg 20165

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1974 ax-7 2015 ax-8 2121 ax-9 2129 ax-10 2152 ax-11 2168 ax-12 2189 ax-ext 2712 ax-sep 5225 ax-nul 5235 ax-pr 5369

This theorem depends on definitions: df-bi 208 df-an 397 df-or 854 df-3an 1094 df-tru 1550 df-fal 1560 df-ex 1787 df-nf 1791 df-sb 2074 df-mo 2543 df-eu 2573 df-clab 2719 df-cleq 2732 df-clel 2815 df-nfc 2889 df-ne 2936 df-ral 3055 df-rex 3065 df-rmo 3345 df-reu 3346 df-rab 3393 df-v 3434 df-sbc 3731 df-dif 3893 df-un 3895 df-in 3897 df-ss 3907 df-nul 4269 df-if 4462 df-sn 4563 df-pr 4565 df-op 4569 df-uni 4846 df-br 5080 df-opab 5142 df-mpt 5161 df-id 5520 df-xp 5631 df-rel 5632 df-cnv 5633 df-co 5634 df-dm 5635 df-iota 6448 df-fun 6494 df-fv 6500 df-riota 7320 df-ov 7366 df-0g 17402 df-mgm 18606 df-sgrp 18685 df-mnd 18701 df-cmn 19755 df-srg 20166

This theorem is referenced by: (None)

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