François G. Dorais

2,600 reputation

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bio	website	mathoverflow.net/users/2000
	location	Hanover, NH
	age	37
visits	member for	2 years, 10 months
	seen	4 hours ago
stats	profile views	317

Mathematician and MathOverflow moderator.

	2,600 reputation	bio	website	mathoverflow.net/users/2000	visits	member for	2 years, 10 months
1023 badges		location	Hanover, NH		seen	4 hours ago

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Jun 8	awarded	Constituent
Jun 8	awarded	Caucus
May 27	comment	A quick question about categoricity in model theory Categorical theory is often used to mean a theory that is $\kappa$-categorical for every infinite cardinal $\kappa$.
Mar 28	awarded	Nice Answer
Feb 6	awarded	Nice Answer
Jan 30	awarded	Nice Answer
Dec 19	comment	How can I prove that the additive group of rationals is not isomorphic to a direct product of two nontrivial groups? Here is an approach: show that any two nontrivial subgroups of $\mathbb{Q}$ have nontrivial intersection. Seems very localized though, I would like to see a more general argument.
Oct 28	comment	Properties of computable numbers There is no effective enumeration of all computable numbers. However, there are effective enumerations of the Turing machines, but not all Turing machines compute real numbers. How should we think of those machines that don't compute real numbers?
Sep 5	revised	What's the difference between these two Venn diagrams? spelling in title
Sep 5	suggested	suggested edit on What's the difference between these two Venn diagrams?
Sep 1	revised	Descriptions of sets and the Axiom of Choice correction
Aug 31	comment	Descriptions of sets and the Axiom of Choice Well, $OD$ is transitive whenever $V = OD$ since $V$ is always transitive, so $V = OD$ and $V = HOD$ mean exactly the same thing.
Aug 31	answered	Descriptions of sets and the Axiom of Choice
Aug 27	answered	Formalizing metamathematics
Aug 23	comment	Can one avoid AC in the proof that in Noetherian rings there is a maximal element for each set? Good point, Arturo. Note that Hodges separates the three definitions in the paper cited above.
Aug 22	comment	Karatsuba vs. Schönhage-Strassen for multiplication of polynomials This answer assumes that the coefficients of the polynomials are integers. I thought that was part of the question, but I now see that it wasn't...
Aug 22	revised	Karatsuba vs. Schönhage-Strassen for multiplication of polynomials small correction
Aug 22	comment	Can one avoid AC in the proof that in Noetherian rings there is a maximal element for each set? Yes, see W. Hodges, Six impossible rings, J. Algebra 31 (1974), 218-244.
Aug 22	answered	Can one avoid AC in the proof that in Noetherian rings there is a maximal element for each set?
Aug 22	revised	Karatsuba vs. Schönhage-Strassen for multiplication of polynomials fixed typo