diracdeltafunk

Los Angeles, CA, USA

http://math.ucla.edu/~benspitz

I love it when really cool things just work.

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Border-radius doesn't affect inner elements

html css border-radius asked Jun 13, 2012 at 5:20

stackoverflow.com

34 votes

Applications of the $\frac{5}{8}$ Theorem

probability abstract-algebra group-theory measure-theory big-list asked May 13, 2019 at 3:53

math.stackexchange.com

20 votes

Is this group free abelian?

group-theory abelian-groups free-abelian-group asked Dec 30, 2023 at 16:36

math.stackexchange.com

19 votes

Remove all elements of an array with non-numeric keys

php arrays associative-array asked Jun 14, 2012 at 23:04

stackoverflow.com

13 votes

Non-isomorphic locally ringed spaces which represent isomorphic functors $\mathsf{CommRing} \to \mathsf{Set}$.

algebraic-geometry representable-functor ringed-spaces asked Mar 10, 2021 at 18:51

math.stackexchange.com

10 votes

Why is $\left(e^{2\pi i}\right)^i \neq e^{-2 \pi}$?

complex-analysis complex-numbers exponentiation asked Aug 9, 2013 at 21:02

math.stackexchange.com

7 votes

How do I plot $x^2+y^2=1$ in 3D?

plotting asked Sep 16, 2012 at 22:39

mathematica.stackexchange.com

6 votes

I cannot install new packages: "Could not get lock /var/lib/dpkg/lock"

ubuntu debian package-management apt dpkg asked Jun 26, 2012 at 22:08

unix.stackexchange.com

5 votes

Find all letters not used in a string

php string asked Apr 30, 2012 at 23:19

stackoverflow.com

5 votes

Which algebraic real numbers are eigenvalues of a finite graph?

graph-theory algebraic-graph-theory spectral-graph-theory algebraic-numbers asked Oct 7, 2020 at 0:26

math.stackexchange.com

Top Answers

Are there statements so self-evident that writing a proof for them is meaningless? Is this an example of one?

math.stackexchange.com

Is there any simple set of properties which uniquely characterizes differentiation?

math.stackexchange.com

Are there any famous/notable mathematicians who have their own YouTube channel?

math.stackexchange.com

Results in linear algebra that depend on the choice of field

mathoverflow.net

is differential geometry really required to understand anything in algebraic geometry?

math.stackexchange.com

Does every commutative ring have $2^n$ idempotents?

math.stackexchange.com

Are functor categories with triangulated codomains themselves triangulated?

mathoverflow.net

Adjoining a function to a ring: what is this called?

math.stackexchange.com

Cannot become ring because distribution law does not hold

math.stackexchange.com

Did S. Lang prove Kuratowski–Zorn lemma without Axiom of choice or Well-ordering theorem?

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Is a surjective immersion a submersion?

math.stackexchange.com

Are There Always More Conjugacy Classes in the Kernel of a Morphism to $\Bbb Z_2$ than Not?

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Must positive operators be self-adjoint on real vector space?

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How does the coefficient ring influence the Euler characteristic?

math.stackexchange.com

Show by hand : $e^{e^2}>1000\phi$

math.stackexchange.com

Is the symmetric group S3 a direct product of nontrivial groups?

math.stackexchange.com

Does this topology have a name?

math.stackexchange.com

Trying to determine $\mathbb{Z}[x] / (6, 2x - 1)$

math.stackexchange.com

Is $\operatorname{FinGrp}^{\operatorname{op}}$ a concrete category?

math.stackexchange.com

Prove there isn't a group $G$ that satisfy ${\rm Aut}(G) \cong \mathbb{Z}$

math.stackexchange.com

The gaussian integers modulo a pair of complex numbers

math.stackexchange.com

Is 𝐴 ∩ 𝒫(𝐴) = ∅ true for A = { 1 } ? Or is 𝐴 ∩ 𝒫(𝐴) = { 1 } ? (Set Theory)

math.stackexchange.com

Showing that a group has infinite order

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Structure Theorem for non-abelian finite groups or rings

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In the category Haus, a continuous map $f:A \rightarrow B$ is an epimorphism iff $f(A)$ is dense in $B$

math.stackexchange.com

What's wrong with the following false-proof that a subspace of a normal space is normal?

math.stackexchange.com

Does hom. $\phi$ from abelian $G$ to $H$ imply $G\cong \ker(\phi)\oplus{\rm im}(\phi)$?

math.stackexchange.com

Can $({\Bbb N}, \max)$ be topologized to be a compact Hausdorff monoid?

math.stackexchange.com

Growth rate of orders of perfect groups

math.stackexchange.com

Injectivity of the canonical map to the double dual

math.stackexchange.com