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Jul
13
comment common multiple polynominal time
What is a common multiple of two real numbers? Or, as an alternative phrasing, why is $1$ not always a solution?
Jul
12
revised The number of partitions of $n$ and the $n$th Fibonacci number.
added 26 characters in body
Jul
12
comment The number of partitions of $n$ and the $n$th Fibonacci number.
The main difference would seem to be that the first is correct notation and the second is meaningless. When $\operatorname{mod}$ is used as an infix function from $\mathbb{Z}\times\mathbb{N}^+$ to $\mathbb{N}$ you shouldn't separate it from its first argument. $(P_n \operatorname{mod} F_n) = P_n$ looks like a bizarre way of writing $0 \le P_n < F_n$, but $P_n = P_n \pmod{F_n}$ just looks like a tautology with a typo of $=$ for $\equiv$.
Jul
12
comment Describing all points 4000 miles from the north pole
It's impossible to answer the underlying question without first determining the model of the globe and the metric. I think that you're modelling the globe as a sphere (as opposed to an ellipsoid such as the WGS84) and measuring the 4000 miles in Euclidean 3-space (as opposed to geodesics on the surface of the globe). Is this correct?
Jul
11
answered Graph Theory, with algorithms like kruskal and something more
Jul
10
reviewed Leave Open How can I find the square root using pen and paper?
Jul
10
reviewed Close Smallest multiple whose digits are only ones and zeros
Jul
10
reviewed Close How to calculate square root or cube root?
Jul
10
reviewed Close A problem with the density of sin (N)
Jul
10
reviewed Close What is the sum that the square root button on calculator does so I can do it without the calculator button
Jul
9
comment Difficulty parsing combinatorics exercise
I read this as counting pairs of partitions ($\lambda$ is a partition into distinct parts of $k$, $\mu$ is a partition into distinct parts of $l$) such that $k+l=m$, $\lambda$ has $n$ more parts than $\mu$ with the complication of the $0$s.
Jul
4
revised Sparsest matrix with full inverse
Change "at most" to "fewer than" to fix argument; add "in that row" to clarify the scope of "exactly"
Jul
3
comment Finding double root of $x^5-x+\alpha$
And then we have $\gcd(x^5 - x + \alpha, 5x^4 - 1)$ $= \gcd(5x^4 - 1, 4x - 5\alpha)$ $= \gcd(4x - 5\alpha, \frac{3125}{256}\alpha^4 - 1)$, so in order for that GCD to be linear we require $\frac{3125}{256}\alpha^4 - 1 = 0$.
Jun
27
comment Looking for different proofs of “Discrete Liouville's Theorem”.
Can you think of a suitable title which includes some non-LaTeX text? Pure LaTeX titles cause some problems.
Jun
27
comment This should be a piece of cake… right?
It wouldn't have cut more than one piece of cake at once, taking the natural meaning of simultaneously. I've edited to remove that adverb and make other clarifications. There's one remaining ambiguity, which I didn't want to resolve because I didn't know in which direction to resolve it: "the cuts may be done however you want" seems to directly contradict "to make it simple, let's say you have a straightedge and a compass".
Jun
27
revised This should be a piece of cake… right?
Clarify most of the ambiguities; tidy for style
Jun
27
comment This should be a piece of cake… right?
If I put the cakes side-by-side and cut through them all parallel to the table in one motion, is that one cut or $n$?
Jun
25
comment The expected outcome of a random game of chess?
@mjqxxxx, I think it's because the chess library considers the game to be over when neither player has enough material to mate, and so breaks the loop, but doesn't consider it to be a stalemate, so it wasn't being counted correctly.
Jun
20
answered Source coding and Entropy
Jun
20
answered Closed form for the Stirling numbers of the second kind.