bio  website  math.psu.edu/petrunin 

location  Penn State  
age  45  
visits  member for  4 years, 5 months 
seen  6 hours ago  
stats  profile views  10,166 
From my son's writing:
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.
11h

answered  Are the higher homotopy groups of the Hawaiian earring trivial? 
18h

comment 
Dimension of a set detected by a homology class
@IgorBelegradek, All this follows directly from the construction. 
18h

comment 
Dimension of a set detected by a homology class
@IgorBelegradek, I think all this standard, isn't it? I only wanted to indicate the construction. 
19h

revised 
Dimension of a set detected by a homology class
+pic 
1d

answered  Dimension of a set detected by a homology class 
2d

comment 
Length inequalities in trees and CAT(0) spaces
Close, but not the same. We ment something like that: mathoverflow.net/questions/7794/ (you will not need the consition on rank. For Lobachevsky space or sphere you need to use hyperbolic/spherical cosine rule instead.) 
2d

reviewed  Approve suggested edit on Projective modules over noncommutative tori? 
2d

reviewed  Approve suggested edit on Drinfeld's noncommutative projective line and noncommutative geometry 
2d

answered  Length inequalities in trees and CAT(0) spaces 
Apr 1 
comment 
A question on the curvature of smooth and embedded curves in a plane
No, check the picture in this question: mathoverflow.net/questions/126128/… 
Mar 31 
awarded  Nice Answer 
Mar 25 
comment 
Isometric embedding of SO(3) into an euclidean space
This is the same as the Veronese embedding $\mathbb{R}\mathrm{P}^3\hookrightarrow \mathbb{R}^9$. 
Mar 25 
comment 
Isometric embedding of SO(3) into an euclidean space
@MarianoSuárezAlvarez OP did not specify the class of embeddings, if it is $C^1$ then by NashKuiper there is one, for $C^\infty$embeddings 9 might be the best. 
Mar 24 
comment 
Buseman function for Riemanniam manifolds with two ends and $Ric\ge (n1)$
No, take double punctured torus (complete metric with constant curvature and finite volume). 
Mar 24 
comment 
Ricci curvature under rough convergence
@ChrisGerig, I do not see ambiguity in the question. In fact it takes some effort to formulate the collapsing version of the statement without optimal transport (try to do this). 
Mar 24 
revised 
Ricci curvature under rough convergence
deleted 2 characters in body 
Mar 23 
comment 
Ricci curvature under rough convergence
P.S. also, it should be known that if $m$dimensional manifolds with lower bound for Ricci curvature GHconverge to an $m$dimensional manifold then it converges in measured GromovHausdorff sense. It is Colding's result if I remember right, likely he also proved the statement you asked. 
Mar 23 
answered  Ricci curvature under rough convergence 
Mar 21 
awarded  Nice Answer 
Mar 17 
reviewed  Approve suggested edit on Gödel's Constructible Universe in Infinitary Logics (A Possible Approach to HOD Problem) 