Reputation
20,745
Next privilege 25,000 Rep.
Access to site analytics
Badges
1 49 119
Impact
~1.4m people reached

23h
comment What is the group of automorphisms of $l^{\infty}$?
The Question should say "W* algebra automorphisms", so reading the comments (which may go away some day) will not be required.
Apr
28
comment Can the topological algebra of analytic functions be endowed with a norm that defines the natural topology?
For the negative answer, you show that the "natural topology" is not "locally bounded" and therefore not normable. [Kelley-Namioka, Problem 2M]
Apr
28
revised Nonzero solutions of an infinite product
added 58 characters in body
Apr
28
answered Nonzero solutions of an infinite product
Apr
27
comment Nonzero solutions of an infinite product
Maybe also needs a note on why $f(a,b)$ continuous in $(a,b)$. Some sort of uniform convergence, I guess.
Apr
24
comment Is there a $C_c^{\infty}( \mathbb{R}^d)$ function whose Fourier transform we can explicitly write down?
First how about a Fourier transform that is not real-analytic?
Apr
21
comment Non-Archimedean non-standard models for R
I think it is more satisfying to write down a concrete model like this. Rather than depend on "compactness" which gives you a model out in "Axiom of Choice Land".
Apr
20
answered Solution of $\left(\Gamma(x+c)/ \Gamma(x+d)\right)y^d/y^c = {\rm const}$
Apr
20
revised Hausdorff dimension of sequence space
deleted 1 character in body
Apr
20
comment Hausdorff dimension of sequence space
It seems to be Indag. Math. not Invent. Math ... corrected ... Besicovitch, A. S. On existence of subsets of finite measure of sets of infinite measure. Nederl. Akad. Wetensch. Proc. Ser. A. 55 = Indagationes Math. 14, (1952). 339–344.
Apr
20
answered Hausdorff dimension of sequence space
Apr
18
comment $l^1$ versus $l^2$
"linearly isomorphic"??? I guess you want your map to be not only linear, but continuous???
Apr
17
comment Is the set of Cauchy spaces a lattice?
Need to provide link like en.wikipedia.org/wiki/Cauchy_space for non-standard terminology.
Apr
17
comment Cardinality of connected Hausdorff topologies
So if two spaces are not homeomorphic, after your "suspension" adding a point and lots of intervals, they are still hot homeomorphic?
Apr
17
comment Non-reflexive Orlicz spaces
@BillJohnson ... "only" $190 from the publisher. And half that in soft cover.
Apr
14
answered How do the roots of a polynomial change when another polynomial is added?
Apr
12
comment Automorphism group of $\mathbf{C}$ over $\overline{\mathbf{Q}}$
"Choice" means the Axiom of Choice. The only non-trivial automorphism of $\mathbf C$ that you can prove exists (without using AC) is complex conjugation. And that does not fix all algebraic numbers.
Apr
12
comment Collatz stopping-time and Poisson distribution, and connection to other problems?
So if you use all the $2$-adic integers, with its Haar measure, then it would have a nice distribution. But corresponding properties upon restricting to the rational integers (a set of probability zero) are not simple to prove, or even (so far) possible to prove.
Apr
10
comment Convolution Integral involving an unknown function
@MichaelRenardy ... That right-hand side is known as a "singular integral". There is a vast literature on that.
Apr
10
awarded  banach-spaces