All Questions

8
votes
1answer
352 views

What is the hardest instance for the group isomorphism problem?

Two groups $(G,\cdot)$ and $(H, \times)$ are said to be isomorphic iff there exists a homomorphism from $G$ to $H$ which is bijective. The group isomorphism problem is as follows: given two groups, ...
1
vote
0answers
37 views

Problems rephrased as quadratic unconstrained binary optimization

I was impressed when i came across Quadratic unconstrained binary optimization (QUBO) recently, and saw how one can rephrase many combinatorial problems into questions about optima of binary functions....
0
votes
1answer
131 views

First-order multi arity functions in dependent type?

(cross posted from Reddit https://www.reddit.com/r/dependent_types/comments/b1ts8b/firstorder_multi_arity_functions_in_dependent_type/? Take Agda for example, functions of multi arity is "encoded" as ...
2
votes
0answers
54 views

Inexpressibility of Second order

In finite model theory, Ehrenfeucht-Fraïssé games gives us tools to prove inexpressibility results for FOL. Pebble games do the same for infinitary logic with finitely many variables. Do we have such ...
5
votes
0answers
125 views

An axiom for John Major's Equality

In the the standard library of Coq, there is the axiom: Axiom JMeq_eq : forall (A:Type) (x y:A), JMeq x y -> x = y. Why isn't it provable? Can it be reduced ...
3
votes
1answer
129 views

How is SDP an extension of spectral algorithms?

In one of his lectures, Uri Feige described semidefinite programming (SDP) as ... an algorithmic technique that extends both linear programming and spectral algorithms. I know the basic ...
3
votes
1answer
132 views

Intuitive explanation behind Goemans-Williamson randomized rounding

A very simple randomized cut algorithm achieves $1/2$ of the optimal value: just choose each vertex to be in the cut with probability $1/2$, independently. Goemans-Williamson does something more ...
3
votes
1answer
115 views

Compressing grammars by introducing ambiguity and left-recursion

This is a reference request. What is known about the following questions? Problem: Given a grammar $G$ (for example context-free) with language $L$ we can introduce a new grammar $G'$ which also ...
3
votes
0answers
59 views

Are there experiments in artificial life on the emergence of sexual reproduction (analogues)?

I'm aware of quite a few experiments on the emergence of replicators in various artificial life areas, e.g. from cellular automata to computer programs. Have any similar result been obtained on the ...
1
vote
0answers
59 views

Confusion about the visibility and arbitration relations in a formal framework for distributed consistency models

In the POPL'14 paper "Replicated Data Types: Specification, Verification, Optimality" and the book "Principles of Eventual Consistency", the authors propose a formal framework for specifying ...
1
vote
1answer
74 views

The SQ argument in Balazs Szorenyi's paper

I am asking about the proof in Theorem 5 (page 6) of this paper, http://www.inf.u-szeged.hu/~szorenyi/Cikkek/sq_d0_ext.pdf Quite a few things about this short argument seem unclear to me, Towards ...
0
votes
1answer
53 views

Counting sum of parities of cycle covers in cubic, planar, bipartite graphs

Let $G$ be a cubic (i.e. every degree exactly three), planar, bipartite graph. By Hall's theorem its edges can be partitioned into three perfect matchings. Take any such partition $M_0,M_1,M_2$ and ...
4
votes
0answers
82 views

Is there a universal gate set for classical probabilistic computing?

We know that NAND gates are universal for deterministic classical circuits, Toffoli gates are universal for reversible deterministic classical circuits, and Clifford+T is universal for quantum ...
2
votes
1answer
118 views

Optimal bounds for $k$-wise non-uniform random bits

Let $k\geq 2$ be a constant (in my case, $k=4$), and $n,t \geq 0$ be integers such that $2^t \leq n$. What is the smallest sample space (or, equivalent, how many true independent random bits are ...
3
votes
0answers
145 views

Take a NEXP-complete problem and then have the input in unary. Why is this not NP-complete?

It is known that if any unary language is NP-complete, then P=NP. Suppose we take a NEXP-complete language with input $x$ in binary and witness $y\in\{0,1\}^{2^{poly(|x|)}}$ such that the verifying ...
8
votes
0answers
220 views

Subset sum problem with at most one solution for any target

This question was originally asked on CS.se. A little bit of initial discussion can be found in the comments there. We first consider the search version of the subset sum problem: Given a set $S$ of ...
4
votes
0answers
137 views

Why is the Toffoli Gate named after Toffoli?

I was reading the following paper: Rolf Landauer, Irreversibility and Heat Generation in the Computing Process, IBM Journal of Research and Development, Volume 5, Issue 3, July 1961. On page 4, ...
11
votes
0answers
175 views

Computational Complexity of the Frobenius Problem

The Frobenius problem takes as input $n$ positive integers $a_1,\ldots,a_n$ with $\gcd(a_1,\ldots,a_n)=1$ and asks for the largest integer $F$ that cannot be written in the form $F=a_1x_1+a_2x_2+\...
1
vote
2answers
81 views

Enumerate all allocations of points in a simplex

Consider the standard 2-simplex $\{(x,y)~|~x+y=1~;~ x,y\geq 0\}$. Given a set $M$ of $m$ points in this simplex, we allocate each point either to X or to Y by the following process: Fix two positive ...
1
vote
1answer
80 views

3 dimensional matching shortest solution NP-hard?

We have array of arbitrary number of elements - 3d vectors with positive integers components - for example ...
3
votes
0answers
56 views

Probability of detecting small bias of a die in the low confidence regime / balls and bins

We are given a biased $m$-sided die: one of the sides has probability $\frac{1}{m} + \gamma$ and all the rest have probability $\frac{1}{m} - \frac{\gamma}{m-1}$ each. The goal is to figure out which ...
1
vote
0answers
35 views

Minimising the maximum distance to the centre of a cluster of points

I have a set of points $C_i$ on a two dimensional plane and I want to find a point $P$ such that the maximum distance from $P$ to any of the points is minimised, i.e. minimise(max($||P-C_i||$)). I've ...
1
vote
2answers
103 views

When is a problem specified on a TM contained in non-uniform classes such as P/poly? [closed]

In this paper by Gottesman and Irani: https://arxiv.org/abs/0905.2419 , they prove NEXP-hardness of tiling an $N\times N$ grid. They do so by encoding a TM in the tiles making up the grid. However, ...
6
votes
1answer
208 views

How to generalize VC dimension?

Let's try to generalize the $VC$-dimension (of the class of hyperplanes) to include accuracy/error. Let $S$ be a set of points in $R^d$ and $t$ in $[0,1]$. We say that the class of hyperplanes $t$-...
7
votes
0answers
288 views

Search in a sorted matrix

A matrix $M$ is sorted if $M_{i,j}\leq M_{i+1,j}$ and $M_{i,j}\leq M_{i,j+1}$. Consider the following problem. Search in a sorted matrix Given a $n\times m$ sorted matrix $M$, where $n\leq m$....
0
votes
1answer
128 views

Data Strcuture to represent dependencies amongst modules

Consider several software modules $m_1, m_2, ... m_n$. Each module has some inputs and outputs and the inputs to some of the modules are dependent on the outputs of some other modes. For example, in ...
5
votes
2answers
109 views

Statistical Distance Growth Given K Independent Copies

Let $X$ and $Y$ be distributions with statistical distance (total variation distance) at most $d$. What is the best upper bound you can give on the statistical distance between $k$ independent copies ...
4
votes
0answers
70 views

Refinement of the hierarchy theorem of a complexity class

Say $\mathrm{CTIME}$ is some complexity measure, syntactic or semantic (e.g. $\mathrm{DTIME}$ or $\mathrm{BPTIME}$). If we already know that for some $f(n) = \omega(n)$, $\mathrm{CTIME}(n) \subsetneq \...
3
votes
0answers
71 views

Reference request: strong polynomial-time for LP

A follow-up of sorts on this question: Complexity of finding a consistent hyperplane What is a good survey of partial results on the strong poly-time status of the general LP problem?
0
votes
1answer
77 views

Confusion about covering number

Problem I do not understand why larger $p$ will give a larger covering number. Since when $p\geq q$, the corresponding hypercube is also larger (by $\| x \| _ { q } \leq n ^ { ( 1 / q - 1 / p ) } \|...
0
votes
1answer
66 views

Question on deduction that a certain problem requires exponential space

My question concern's a statement from the classic paper The equivalence problem for regular expressions with squaring requires exponential space. Regular expressions with squaring are like ordinary ...
3
votes
0answers
64 views

Rearranging angles of a convex polyline to make it closed

Let {$\alpha_1, \alpha_2, ... ,\alpha_n$} be a string of n positive reals summing up to 2$\pi$. We inductively construct the following 2D polyline, denoting with $R[\alpha]$ the clockwise rotation by ...
2
votes
1answer
121 views

Generalizations of linear programming

Linear problems can be solved in polynomial time. So can semidefinite programs and, presumably, many other useful classes of optimization programs. Is there a survey/lecture notes describing ...
1
vote
1answer
108 views

Dependent C-style types with subtyping rule

I'm looking for previous work regarding an extension of a C-style type system in which types may have constraints and have a defined subtyping rule. In particular, I'm interested in defining algebra-...
0
votes
1answer
37 views

Does fixed hyperparameters perform well regardless the number of training examples?

I'm new in this community and I don't know whether my question is proper for this community. I will delete this post if it is not proper. I'm interested in deep learning network models and have a ...
2
votes
0answers
36 views

Time complexity of finding a point of infinite order on a rank 1 elliptic curve over Q

As an outsider, it sounds like a lot of progress has been made on understanding rank 1 elliptic curves over Q. Much of the BSD conjecture is known for rank 1, and Heegner points provide a way in ...
8
votes
1answer
211 views

Depth reduction for Boolean circuits

This result by Tavenas, Koiran and others show that any polynomial computed by a circuit of size $s$ is computed by a depth-4 homogenous circuit of size $s^{\sqrt{d}}$. Are there any similar results ...
1
vote
0answers
49 views

Anagrams, Prime numbers and prime coding [closed]

I am from math.stackexchange, here is my original post. https://math.stackexchange.com/questions/2354828/anagrams-prime-numbers-and-prime-number-coding The only comment I received was too technical ...
1
vote
0answers
69 views

A question on the Kolmogorov Complexity of Human I/O behaviour

Note: From my Twitter poll I managed to get feedback from AI researchers and neuroscientists so far and I think it would be interesting to get input from theoretical computer scientists on this ...
5
votes
1answer
199 views

How to tell if an effect is algebraic?

I've read Bauer's What is algebraic about algebraic effects and handlers? and he talks about IO being an algebraic effect, even though it doesn't have any equations. In other papers on algebraic ...
1
vote
0answers
70 views

LSH Probabilistic guarantees

A family $H$ is $(r,cr,p_1,p_2)$-sensitive if for all $x,y \in \mathbb{R}^d$ we have: $\lVert x-y\rVert <r\quad \Rightarrow\quad \Pr[h(x)=h(y)] \geq p_1$, and $\lVert x-y\rVert > cr \quad \...
3
votes
0answers
89 views

Generating a random connected bipartite graph

A (n, m, k)-bipartite graph is a bipartite graphs with: independent sets of size $\{n, m\}$ a total of $k \geq n+m-1$ edges We want an algorithm to generate a (n, m, k)-bipartite selected uniformly ...
3
votes
0answers
112 views

Dequantumizability known and unknown?

Dequantumizable problems have been taking some headlines these days (for example https://www.scottaaronson.com/blog/?p=3880 and https://www.quantamagazine.org/teenager-finds-classical-alternative-to-...
4
votes
0answers
69 views

Optimal scheduling with delay constraints

Suppose you have $K$ servers numbered $\{1,2,...,K\}$. Playing server $i$ provides a value of $v_i > 0$. However, once you play server $i$, you are not allowed to play it for the next $n_i$ time-...
6
votes
1answer
228 views

Example problem that is not in $2^{o(n)}$ but could be solved in $O(2^{cn})$ for any $c > 0$ (suggested by wording of ETH)

In the wikipedia article on Time Complexity it is written that: The exponential time hypothesis (ETH) is that 3SAT, the satisfiability problem of Boolean formulas in conjunctive normal form with, ...
1
vote
1answer
47 views

Extending EAL with recursion makes it incompatible with the abstract algorithm?

A few years ago, I've asked if Elementary Affine Logic can be used as the core type system of a practical programming language. The accepted answer argues that, yes, although such language would be ...
0
votes
1answer
69 views

Why are all finite languages regular? [closed]

It is said that "All finite languages are regular". But the Pumping Lemma says that, if a language is regular one can find a 'large-enough' word w such that it can be decomposed into w = xyz such ...
2
votes
1answer
183 views

What are CS blogs for puzzles/games?

I am looking for blogs which contains recent progress on puzzles/games (Algebraic and Combinatorial) etc. like Soduko, latin square etc. I come across a list on TCS What CS blogs should everyone read?,...
1
vote
0answers
243 views

On $BPP$ in $P^{NP}$ and $SETH$

It is believed showing $BPP$ in $P$ involves good $PRG$s and faces lower bound barriers. Does showing $BPP$ in $P^{NP}$ which would mean $BPP\neq EXP^{NP}$ face similar $PRG$ and give lower bounds? ...
1
vote
1answer
76 views

About learning a single Gaussian in total-variation distance

I am looking for the proof of this following result which I saw as being claimed as a "folklore" in a paper. It would be helpful if someone can share a reference where this has been shown! Let $G$ ...

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