# Zsbán Ambrus

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 Name Zsbán Ambrus Member for 3 years Seen 2 hours ago Website Location Age
I'm a mathematician currently working in informatics, and at the same time a grad student researching graph theory.
 May5 comment roots of polynomial with matrix coefficientsIs A and X the same? May3 comment Decidability of equality of expressions built using 1,+,-,*,/,^I believe there is such an algorithm but it's quite complicated. Apr25 comment Does Physics need non-analytic smooth functions?You should ask this question on physics.stackexchange.com instead of here. (Btw, does "in nature" mean you don't examine physicists in carefully conducted laboratory experiments like xkcd.com/669 ?) Apr23 comment Can a nowhere continuous function be integrable ?Ah right, Cantor set. Sorry. Ignore what I said then, and take what Loïc Teyssier says. Apr22 accepted Can a nowhere continuous function be integrable ? Apr22 answered Can a nowhere continuous function be integrable ? Apr22 comment Can a nowhere continuous function be integrable ?@Hentry Wen: Henr.L is right, that function is everywhere discontinuous, because it takes the value 0 and 1 in every interval. Apr15 comment The average number of people that can sit on a bench of a given length.Keyword to search for: online bin packing, next fit. Apr14 revised Old books still usedadded 48 characters in body Apr13 awarded ● Yearling Apr10 comment The shortest mathematical paper@Martin Brandenburg: instead of your first link, do you mean mathoverflow.net/questions/7330/… ? Apr10 answered The shortest mathematical paper Apr4 comment Checkmate in $\omega$ moves?Nice! This solution actually seems more easy to understand than the others. Mar28 revised Visualizing polyhedra from their 1-skeletonsreferences again Mar28 answered Visualizing polyhedra from their 1-skeletons Mar20 awarded ● Citizen Patrol Mar19 comment “Mathematics talk” for five year oldsI agree with Douglas Zare. For example, even as an adult, I can't make a convincing drawing of Pappus's theorem (Pascal's theorem applied on two lines used a degenerate conic) come out right if drawn with a straightedge. Mar10 comment When has pure mathematics been influenced by the social context of mathematicians?Does the death of Archimedes count? The social context has caused his death, and you can find exaggerated claims about how much he could have advanced mathematics and science and engineering if he lived longer. Feb24 comment Awfully sophisticated proof for simple factsCould you derive this result from supposing Goldbach's conjecture? Feb24 comment Awfully sophisticated proof for simple factsNote that Michael Greinecker has also mentioned Baryshnikov's proof in an earlier reply. Feb22 comment Is integer GCD in NC? Jan28 comment Diophantine equation solutionsCould you change the title to something more specific, such as "Difference of two complete powers"? Jan25 accepted Graphs with circulant distance matrices Jan25 answered Graphs with circulant distance matrices Jan18 answered Majority vote of total orders Jan15 comment How should one present curl and divergence in an undergraduate multivariable calculus class?Have you tried to start with the two-dimensional analogs first? Once the students understand the theorems in two dimensions (both the differential and the integral forms), you can motivate curl by saying that it's what makes it possible to have analogous theorems in three dimensions. Jan14 revised Proving a determinant = 0edited formulas in proof using (D), for I've made a mistake previously. Jan13 answered Proving a determinant = 0 Jan9 comment computational complexityI see. This likely works, though I admit I couldn't tell how to prove that the complex can't accidentally contain a sphere. Interesting. Jan9 comment computational complexityIn your construction, wouldn't two discs filling the same hole form a 2-sphere already? Jan7 comment Are All Irrational Elementary Numbers Conjectured to Be Normal?Are floors allowed in the equation? If so, you can likely construct a non-normal number with techniques similar to how the logicians prove first-order statements quantified on natural numbers with just addition and multiplication can encode anything. If not, I still think it's likely you can do something similar. Jan2 answered Old books still used Dec27 comment Why is a ring called a “ring”?See also jeff560.tripod.com/r.html Dec25 comment Smallest sphere intersecting lines in R^3Wait what? The maximum of convex functions needn't be convex. For example, in one dimension, $max(x, -x)$ is not convex despite that $x$ and $-x$ both are. Dec17 comment What is the simplest known arithmetic definition of exponentiation?Juat to clarify, the quantifiers are on variables over natural numbers, and the quantifier-free formula can contain equality, addition and multiplication of natural numbers, right? Dec1 awarded ● Necromancer