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visits member for 4 years, 4 months
seen Dec 15 at 20:53

Dec
15
awarded  Caucus
Jul
30
comment Why is the volume of a sphere $\frac{4}{3}\pi r^3$?
The negative solution to Hilbert's third problem (en.wikipedia.org/wiki/Hilbert%27s_third_problem) strongly suggests (if not shows outright) that this and related questions require calculus in an essential way, and that calculus-free "derivations" are just hiding something.
Jul
2
awarded  Curious
Apr
29
comment Meaning of pullback
Consider $f = g \circ \alpha$. The universal property implies that the corresponding pullback satisfies (using Wikipedia notation current at the time of writing) $P = \text{dom } \alpha$, $p_1 = id$, $p_2 = \alpha$, so that $\alpha$ is the pullback of $f = g \circ \alpha$ along $\alpha$.
Jan
22
comment How can I explicitly construct a *nice* conformal mapping from a triangle to a square in MATLAB?
let us continue this discussion in chat
Jan
22
comment How can I explicitly construct a *nice* conformal mapping from a triangle to a square in MATLAB?
@Arkamis--Look at the polygon p1. The stuff you're preoccupied with doesn't have anything to do with the actual polygon, just an easy way to generate points inside it.
Jan
22
comment How can I explicitly construct a *nice* conformal mapping from a triangle to a square in MATLAB?
I should also note that I've seen mathfaculty.fullerton.edu/mathews/c2003/… and this (or similar maps) doesn't really solve my problem AFAIK.
Jan
22
comment How can I explicitly construct a *nice* conformal mapping from a triangle to a square in MATLAB?
@Arkamis--I don't think so. That's just the y-limits of the equilateral triangle, which is centered at the origin.
Jan
22
asked How can I explicitly construct a *nice* conformal mapping from a triangle to a square in MATLAB?
Aug
31
accepted Reference request for Euclidean metric in hyperspherical coordinates
Aug
31
asked Reference request for Euclidean metric in hyperspherical coordinates
Jul
26
comment Number of item distributions in buckets of different sizes
@VladimirDotsenko: I wish I could have read your comment back in 2001!
Jul
26
comment Number of item distributions in buckets of different sizes
I would hope that this is not closed: if there is a simple answer, I am not aware of it and would like to know it. I previously wondered about this very question many years ago and based on that experience I do not think it should be migrated. For instance, I could not figure out how to make the straightforward appeal to inclusion-exclusion actually work in practice.
Jul
26
comment Number of item distributions in buckets of different sizes
The case where $c_b \ge I$ gives $\binom{I+B-1}{I}$, by "stars and bars": en.wikipedia.org/wiki/Stars_and_bars_(combinatorics)
Dec
8
accepted What discrete memoryless channels have zero capacity?
Dec
6
comment What discrete memoryless channels have zero capacity?
Edited to remove the question's ambiguity.
Dec
6
revised What discrete memoryless channels have zero capacity?
added 29 characters in body
Nov
30
asked What discrete memoryless channels have zero capacity?
Sep
14
accepted Boolean circuits and digraphs
Sep
13
revised Boolean circuits and digraphs
added 142 characters in body