141 reputation
4
bio website chrisphan.com
location Winona, MN
age 33
visits member for 4 years, 1 month
seen 13 hours ago

For information about me, see my web site.


Jul
18
awarded  Commentator
Jul
18
comment Prove $18080108080 \sum_{k=0}^{1560-1} 10^{10k}+1$ is prime
Some discussion on verifying the primality of this number can be found in this blog post and its comments.
Aug
5
comment Is $\large \frac {\pi}{e}$ rational, irrational, or trandescendal?
You might want to take a look at this: math.stackexchange.com/questions/456097/…
Apr
11
comment Definition of chain (Rudin)
It's an element of the free abelian group whose basis is the set of all paths.
Mar
2
comment Commutator subgroup question
You need to show $(aC)(bC)$ and $(bC)(aC)$ are equal. When are things are equal in a quotient group?
Mar
2
comment “Such that” symbol “$\mid$”
I'm not sure that the goal of formal notation is "international comprehension". Besides, it's difficult to have a substantive conversation about mathematics without employing words as well as notation.
Feb
20
comment A sequence of continuous functions converging to a discontinuous function
For a problem like this, I think it's easiest to start with an example of such an $f$ (and keep it simple, say one discontinuity) and then come up with a series of continuous functions $f_n$ that make better and better approximations of $f$. Once you do this for an example, you have a better idea how to do it for any such $f$.
Feb
6
comment For what coinage systems does a greedy algorithm not work in providing change?
Here's a paper that summarizes some of what's known about this problem: A. Adamaszeka and M. Adamaszek, "Combinatorics of the change-making problem", European Journal of Combinatorics, Volume 31, Issue 1, January 2010, Pages 47–63. (dx.doi.org/10.1016/j.ejc.2009.05.002)
Dec
12
comment How should I assign RGB colors to points in the Mandelbrot Set?
Perhaps use the HSV color space instead of RGB?
Dec
10
awarded  Teacher
Dec
9
answered Using Wolfram Alpha to output table of values over the integers
Oct
18
comment LOVE +MATH = can you read this formula?
Perhaps you found the image here: mathematische-basteleien.de/heart.htm (That's what came up when I used Google image search.)
Dec
13
awarded  Supporter
Jul
27
awarded  Autobiographer