All Questions
-2
votes
0answers
26 views
Sorting a subset of a sorted set; does it need the merge sorting complexity?
Suppose that we have an algorithm in which we have a sorted list of objects like $L = (x_1, x_2, \ldots, x_n)$ (the indices denote the order of the objects). During the algorithm we have a loop where ...
4
votes
1answer
68 views
NP-Complete Static Square Puzzles
In order to empirically test some CSP algorithms, I would like to compile a list of NP-Complete static board games. By static, I mean that a solution of the puzzle is simply an assignment of values to ...
4
votes
0answers
55 views
Expander Graph from Hypergraph
I came up with this problem while thinking about an optimizing compiler.
Let $H$ be a hypergraph. From this we construct a graph $G_H$ as follows the vertices are the hyperedges of the hypergraph. ...
5
votes
0answers
59 views
Direct Proof that the Pigeonhole Principle is Hard for Regular Resolution
It is well known that the pigeonhole principle $PHP_n^{n+1}$ is hard for general resolution. The original proof due to Haken is elegant. One first defines a complexity measure for derived clauses, in ...
-1
votes
0answers
48 views
Is this problem involving shortest paths NP hard?
A graph with positive edges is given along with several vehicles at specific vertices of the graph.One of the vehicles has a package that is required to be transferred to a destination node.The ...
1
vote
1answer
42 views
A coupon collector type problem with changing probabilities
Suppose we are flipping coins starting at some time $t$. At time $t$ the probability we obtain heads is $\frac{1}{\sqrt{t}}$. If the coin lands tails, at time $t+1$ the probability of heads is now $\...
-1
votes
0answers
30 views
How to randomly sample a social graph to find paths between at least 20% of profiles?
Given a Graph, where we know
Total number of nodes (~100,000)
Average no of connections per node (~200)
Maximum distance between two nodes (~5)
How many nodes (and its connections) do we have to ...
-2
votes
0answers
38 views
Channel capacity as a limit on information storage
It is well-known that Shannon's channel capacity provides an upper bound on the amount of information (measured in bits/s) that can be reliably (i.e. with vanishing decoding error probability) ...
10
votes
1answer
103 views
Linear circuit complexity classes
The class $\textrm{NC}^i$ is the class functions computable by circuits families of bounded fan-in, $n^{O(1)}$ size and $O(\log^i(n))$ depth.
The $\textrm{NC}$-hierarchy is the union of those classes....
2
votes
0answers
46 views
Linear optimization over intersection of totally unimodular matrices
I am currently dealing with a problem of the following form
\begin{alignat}{2}
&\underset{x, y \in \mathbb{R}^n}{{\text{min}}} && e^T x \nonumber\\
&\text{sub to} \hspace{0.05in}&&...
10
votes
1answer
724 views
Number of 4 cycles
Let $C_4$ be a cycle with four vertices. For an arbitrary graph $G$ with $n$ vertices and m edges say $m>n\sqrt n$, how many $C_4$s exist? Is there a lower bound for this?
3
votes
2answers
370 views
Is there a non-deterministic version of the complexity class PP?
From a quick skim of the literature (and complexity zoo), there doesn't seem to be a non-deterministic version of PP. Is there a reason for this (e.g. PP=non-deterministic PP?)
Edit: Perhaps I ...
1
vote
0answers
38 views
Average margin bounds for separable SVM
Suppose we're training a linear separator in the realizable PAC setting. Given $m$ labeled examples $(x_i,y_i)$ in $\mathbb R^d\times\{-1,1\}$, a (consistent) linear separator is a vector $w\in\mathbb ...
8
votes
1answer
186 views
Is algorithmic information theory still evolving?
I am currently looking for a subject for a thesis and encountered the field of algorithmic information theory.
The field seems very interesting for me, but it seems everything is the field was done ...
6
votes
0answers
85 views
Complexity of fractional SAT
Let $(a, k)$-SAT be $k$-SAT with the promise that if there is there is a satisfying assignment, then there is such an assignment that satisfies at least $a$ literals of every clause. Can 3-SAT with $...