All Questions
5 questions
12
votes
2
answers
621
views
“The Two Sheriffs” puzzle -2: threshold for security
I've already asked a question “The Two Sheriffs” puzzle with wrong assumption. Yoav Kallus in his amazing answer using Fano plane showed that the problem has a solution in the case of seven suspects.
...
6
votes
1
answer
441
views
Minimum number of operations necessary to arrive at any configuration
Let $k \geq 2$ and $N_1, N_2, ..., N_k$ be positive integers.
Let $S=\{(a_1,a_2,...,a_k) \in \mathbb{Z}^k:1 \leq a_i \leq N_i\}$ and $A=\{1,2,...,\prod_{i=1}^{k} N_{i}\}$.
Given a bijective map $f:...
5
votes
2
answers
496
views
Maximum number of vectors with upper bound on pairwise inner products
I have a collection $\{v_1,...,v_k\}$ of vectors in $\{\pm 1\}^n$ with the property that for all $i\neq j$ we have $\langle v_i, v_j \rangle \le c\log_2(n)$. I am looking for an upper bound on $k$ in ...
2
votes
1
answer
262
views
Are there any homomorphic analog error correction code?
Are there any analog error correction codes that are additively and multiplicatively homomorphic?
2
votes
1
answer
316
views
Is this model of converting integers to Gray code correct?
The model shown in the figure converts all numbers that have k digits in the binary system to Gray code without any calculation, but I have no proof that guarantees this claim.
Here is some ...