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Aug 26 at 23:24 vote accept stupid_question_bot
S Aug 26 at 18:59 vote accept stupid_question_bot
Aug 26 at 23:24
Sep 13, 2021 at 23:22 history edited stupid_question_bot CC BY-SA 4.0
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Sep 13, 2021 at 23:21 history edited Will Chen CC BY-SA 4.0
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Sep 13, 2021 at 19:54 vote accept stupid_question_bot
S Aug 26 at 18:59
Sep 13, 2021 at 19:54 answer added stupid_question_bot timeline score: 6
Sep 8, 2021 at 14:02 history edited stupid_question_bot CC BY-SA 4.0
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Sep 8, 2021 at 8:59 answer added Wilberd van der Kallen timeline score: 14
Sep 8, 2021 at 3:16 history edited stupid_question_bot CC BY-SA 4.0
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Sep 7, 2021 at 7:35 comment added Wilberd van der Kallen It must be true because Donkin shows one has a good filtration over $\mathbb Z$. That implies base change for the group scheme invariants. Infinite fields are only needed when one wants to confuse a group $G(k)$ with the group scheme $G_k$.
Sep 7, 2021 at 7:15 comment added stupid_question_bot @darijgrinberg They seem to cover the cases of $R = \mathbb{Z}$ or $R$ an infinite field (see their proof in $\S15.2$)
Sep 7, 2021 at 7:14 history edited stupid_question_bot
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Sep 7, 2021 at 4:33 history edited YCor CC BY-SA 4.0
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Sep 7, 2021 at 4:13 comment added user44191 It might be worth adding the [quivers] tag, as this is asking about the invariants for the one-vertex, d-loop quiver.
Sep 7, 2021 at 3:02 history edited stupid_question_bot CC BY-SA 4.0
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Sep 7, 2021 at 2:22 history edited stupid_question_bot CC BY-SA 4.0
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Sep 7, 2021 at 2:14 comment added stupid_question_bot @LSpice The Sibirski result is cited in the introduction to Donkin's paper, though I have not checked it. Here's the citation: "Sibirski, K.S.: On unitary and orthogonal matrix invariants. Dokl. Akad. Nauk. SSSR 172, 1, 40-43 (1967)"
Sep 7, 2021 at 1:50 comment added darij grinberg FWIW: This is also part of Theorem 1.10 in Corrado De Concini, Claudio Procesi, The Invariant Theory of Matrices, AMS 2017. But I'm not quite sure what they require of the base ring $R$; possibly it has to be a field. (But algebraic closedness can certainly not be useful; the claim is of the form "a vector lies in the span of a bunch of other vectors", so must hold in any prime field if it holds in an extension.)
Sep 6, 2021 at 23:57 comment added LSpice Could you give a reference to the classical result? MathSciNet does not seem to recognise Sibirski.
Sep 6, 2021 at 23:57 history edited LSpice CC BY-SA 4.0
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Sep 6, 2021 at 23:31 history asked stupid_question_bot CC BY-SA 4.0