# Tagged Questions

**5**

votes

**1**answer

453 views

### Difference Sets

Suppose
$$
P \subseteq \{1,2,\dots,N\},\quad |P| = K
$$
We calculate the differences as: $$d=p_i-p_j\mod N,\quad i\ne j$$
Now let $a_d$ denote the number of occurrence of $d$ (for $d = 1, 2, \dots , N ...

**7**

votes

**1**answer

340 views

### Building a polyhedron from areas of its faces

Is there a known algorithm which, given a finite multiset (unordered list) of integers $A$, returns a yes/no answer for ...

**0**

votes

**1**answer

253 views

### [Matrices over Z] - An algorithm for calculating the diagonal with elementary operations

Dear mathoverflow,
Let
$
\left(
\begin{array}{cc}
a & b \newline
c & d
\end{array}
\right)
$
be a matrix with $a, b, c, d \in \mathbb{Z}$, $\gcd(a,b,c,d) = 1$ and $ad - bc = \pm N$, with $N ...

**13**

votes

**0**answers

1k views

### Minimum tiling of a rectangle by squares

Given the $n\times m$ rectangle, I want to compute the minimum number of integer-sided squares needed to tile it (possibly of different sizes).
Is there an efficient way to calculate this?