Harry Altman

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Name	Harry Altman
Member for	3 years
Seen	11 hours ago
Website	www-personal.umich.edu/~haltman
Location	Ann Arbor, MI
Age	26

Graduate student at University of Michigan. Figured out some stuff about integer complexity with Joshua Zelinsky.

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649

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Surreal exponentiation — are the varying definitions equivalent? If not, is there agreement on which ones are better?

feb 21 12 at 4:40 Philip Ehrlich 1,289●1●5●11

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answers

280

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Start with a topological group, take the meet of the two uniformities, and take the topology. Is the result again a topological group? [xpost from math.SE]

gn.general-topology gr.group-theory topological-groups uniform-spaces

oct 19 at 20:42 Mikael de la Salle 3,466●5●16

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516

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Lower bound on # of nonzero digits in ternary expansions of powers of 2?

nt.number-theory digits

jul 3 10 at 19:16 Mike Bennett 946●6●8

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794

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Does “finitely presented” mean “always finitely presented”, considered in general

gr.group-theory ra.rings-and-algebras ac.commutative-algebra abstract-algebra universal-algebra

jan 15 11 at 17:24 Yiftach Barnea 2,310●1●10●18

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803

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Finite dimensional vector spaces over a complete but not-necessarily-valued field

gn.general-topology linear-algebra topological-groups uniform-spaces fields

sep 22 11 at 7:13 Harry Altman 980●1●10●16

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215

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Does the weak approximation theorem hold for general topological fields?

gn.general-topology linear-algebra topological-groups uniform-spaces fields

sep 8 11 at 7:01 Harry Altman 980●1●10●16

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225

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What are these operations on ordinals, analogous to multichoose, called? [xpost from Math.SE]

lo.logic reference-request set-theory ordinal-numbers order-theory

feb 19 12 at 4:13 Harry Altman 980●1●10●16

Answers

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What are the most attractive Turing undecidable problems in mathematics?

Examples of seemingly elementary problems that are hard to solve?

Examples of common false beliefs in mathematics.

Axiomatic definition of integers

Theorems with unexpected conclusions

Not especially famous, long-open problems which anyone can understand

How this set of functions is ordered?

Combinatorial Inequality

Algebraically closed fields with proper maximal subfields

Non-inversible monoids

Naturally occurring orderings

Open problems with monetary rewards (2)

Subspaces of End(V) that can fix any vector (2)

Trichotomies in mathematics

A problem of an infinite number of balls and an urn

What’s your favorite equation, formula, identity or inequality?

Suggestions for good notation

Does the weak approximation theorem hold for general topological fields?

Finite dimensional vector spaces over a complete but not-necessarily-valued field

Partition into connected sets by proximity

Union of proximally connected sets

758

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698

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Questions

Surreal exponentiation — are the varying definitions equivalent? If not, is there agreement on which ones are better?

Start with a topological group, take the meet of the two uniformities, and take the topology. Is the result again a topological group? [xpost from math.SE]

Lower bound on # of nonzero digits in ternary expansions of powers of 2?

Does “finitely presented” mean “always finitely presented”, considered in general

Finite dimensional vector spaces over a complete but not-necessarily-valued field

Does the weak approximation theorem hold for general topological fields?

What are these operations on ordinals, analogous to multichoose, called? [xpost from Math.SE]

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