Anton Petrunin

Penn State

http://www.math.psu.edu/petrunin/

A description by my son:

Mein Vater hat keine Haare aber er hat einen schwarzen Bart. Er hat grüne Augen so wie ich. Er benutzt seine Brille sehr selten. Sein Name ist Tosha. Er mag Musik spielen aber ist ganz schlecht dabei und ist 44 Jahre alt.

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Is a free alternative to MathSciNet possible?

online-resources math-communication mathscinet zbmath asked Feb 1, 2010 at 3:41

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122 votes

One-step problems in geometry

dg.differential-geometry mg.metric-geometry big-list mathematics-education asked Dec 8, 2009 at 20:56

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94 votes

Elementary+Short+Useful

big-list mathematics-education asked Apr 3, 2011 at 17:34

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46 votes

Can I wrap a suitcase with hair ties

at.algebraic-topology knot-theory knot-link asked Jun 7, 2022 at 21:29

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42 votes

Many flat totally geodesic surfaces ⇒ flat?

dg.differential-geometry riemannian-geometry asked Jan 1, 2011 at 23:57

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36 votes

Two-convexity ⇒ Lefschetz?

convexity convex-geometry morse-theory missing-lemma asked Feb 17, 2011 at 22:12

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36 votes

Bodies of constant width?

mg.metric-geometry discrete-geometry convex-polytopes constant-width asked Jan 26, 2012 at 17:57

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32 votes

Term for "uncheckable constructions"

mg.metric-geometry terminology euclidean-geometry plane-geometry geometric-constructions asked Nov 16, 2014 at 21:04

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31 votes

Optic fibers after Joseph O'Rourke

ds.dynamical-systems billiards asked Oct 8, 2011 at 5:53

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30 votes

Diameter of m-fold cover

mg.metric-geometry asked Dec 4, 2009 at 0:28

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Top Answers

Elementary+Short+Useful

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Famous mathematical quotes

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Which mathematicians have influenced you the most?

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Elementary+Short+Useful

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Your favorite surprising connections in mathematics

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Do you know important theorems that remain unknown?

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An inequality for cosine of n

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Finite set of non-collinear points on plane with every point having ≥ 3 equidistant neighbors?

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Does a Riemannian manifold with bounded geometry admit an isometric proper embedding into Euclidean space with uniformly thick tubular neighborhood?

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Why are isometries of Minkowski space necessarily linear?

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Light rays bouncing in twisted tubes

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Is the "Napkin conjecture" open? (origami)

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Are there smooth bodies of constant width?

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Contractibility of the space of Jordan curves

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Is Euclid dead?

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Acute triangles in "obtuse" polygons?

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Shortest path connecting two opposite points on a cube

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Is a function with nowhere vanishing derivatives analytic?

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Can a connected planar compactum minus a point be totally disconnected?

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Can a Riemannian metric be analytic in non-analytically different coordinates?

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Suggestions for good notation

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Converse to Stokes' Theorem

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Mathematical "urban legends"

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Can every Lie group be realized as the full isometry group of a Riemannian manifold?

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Which metric spaces have this superposition property?

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Is every smooth function Lebesgue-Lebesgue measurable?

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Down-To-Earth Uses of de Rham Cohomology to Convince a Wide Audience of its Usefulness

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Which mathematicians died very young or in a tragic way?

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Feasibility of a list of prescribed distances in R^3

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Space of metrics with positive sectional curvature

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