Theorem fldextsubrg 34392

Description: Field extension implies a subring relation. (Contributed by Thierry Arnoux, 29-Jul-2023.)

Hypothesis

Ref	Expression
fldextsubrg.1	⊢ 𝑈 = (Base‘𝐹)

Assertion

Ref	Expression
fldextsubrg	⊢ (𝐸/FldExt𝐹 → 𝑈 ∈ (SubRing‘𝐸))

Proof of Theorem fldextsubrg

Step	Hyp	Ref	Expression
1		fldextsubrg.1	. 2 ⊢ 𝑈 = (Base‘𝐹)
2		fldextfld1 34390	. . . . 5 ⊢ (𝐸/FldExt𝐹 → 𝐸 ∈ Field)
3		fldextfld2 34391	. . . . 5 ⊢ (𝐸/FldExt𝐹 → 𝐹 ∈ Field)
4		brfldext 34388	. . . . 5 ⊢ ((𝐸 ∈ Field ∧ 𝐹 ∈ Field) → (𝐸/FldExt𝐹 ↔ (𝐹 = (𝐸 ↾s (Base‘𝐹)) ∧ (Base‘𝐹) ∈ (SubRing‘𝐸))))
5	2, 3, 4	syl2anc 596	. . . 4 ⊢ (𝐸/FldExt𝐹 → (𝐸/FldExt𝐹 ↔ (𝐹 = (𝐸 ↾s (Base‘𝐹)) ∧ (Base‘𝐹) ∈ (SubRing‘𝐸))))
6	5	ibi 270	. . 3 ⊢ (𝐸/FldExt𝐹 → (𝐹 = (𝐸 ↾s (Base‘𝐹)) ∧ (Base‘𝐹) ∈ (SubRing‘𝐸)))
7	6	simprd 501	. 2 ⊢ (𝐸/FldExt𝐹 → (Base‘𝐹) ∈ (SubRing‘𝐸))
8	1, 7	eqeltrid 2868	1 ⊢ (𝐸/FldExt𝐹 → 𝑈 ∈ (SubRing‘𝐸))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1570   ∈ wcel 2147   class class class wbr 5108  ‘cfv 6566  (class class class)co 7451  Basecbs 17431   ↾_s cress 17452  SubRingcsubrg 20872  Fieldcfield 21032  /_FldExtcfldext 34381

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-ext 2735  ax-sep 5255  ax-pr 5398

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-sb 2102  df-clab 2742  df-cleq 2755  df-clel 2839  df-ral 3081  df-rex 3091  df-rab 3417  df-v 3456  df-ss 3901  df-dif 4050  df-in 4094  df-un 4154  df-nul 4282  df-if 4486  df-sn 4589  df-pr 4591  df-op 4841  df-uni 4873  df-br 5109  df-opab 5174  df-xp 5664  df-iota 6520  df-fv 6574  df-ov 7454  df-fldext 34384

This theorem is used by:  fldextsdrg  34397  fldextsralvec  34398  extdgcl  34399  extdggt0  34400  extdgmul  34406  extdg1id  34409  fldextchr  34412