Tagged Questions

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2
votes
0answers
69 views

Pseudorandom generators indistinguishable by uniform deterministic adversaries

I've seen pseudorandom generators defined for nonuniform efficient adversaries, or uniform probabilistic efficient adversaries. (For example, a monograph Pseudorandomness by Vadhan (here's its draft ...
6
votes
1answer
88 views

Are there presentations of set theory in terms of lambda-calculus?

I am planning to implement in software a set theory language, based on a binary function, which in set theory is the so called adjunction operation: $f(x, y) = x \cup$ {y}. Therefore, a presentation ...
7
votes
3answers
145 views

How high are the higher types that appear in practice?

This is admittedly a rather naively put and vague question, and I'm not sure how much more specific I want or can make it, but I'll try. By "practice" I mean surely in actual programming practice (of ...
8
votes
3answers
287 views

EXPSPACE-complete problems

I am currently trying to find EXPSPACE-complete problems (mainly to find inspiration for a reduction), and I am surprised by the small number of results coming up. So far, I found these, and I have ...
0
votes
1answer
35 views

Reference request: Classical analog of quantum threshold theorem

For quantum circuits, once the gate error is below a threshold, the error probability of an entire computation can be driven exponentially small with polylog costs in time and space: ...
10
votes
2answers
220 views

What is the minimum over all distributions of unit vectors of the variance of the dot product of the vectors?

I am trying to find a distribution over $n$ random vectors, say $x_1,\ldots, x_n$, on the $k$-dimensional unit sphere (where $n > k$) that minimizes $\max_{i\neq j} \mathrm{Var}(x_i^T x_j)$ subject ...
2
votes
2answers
91 views

Graph-theoretic properties of the Wiener index

The Wiener index of a graph is the sum of the lengths of the shortest paths between all pairs of its vertices. Are there useful graph-theoretic properties of this index?
2
votes
1answer
60 views

Weighted furthest point voronoi diagrams

I found that Weighted nearest neighbor voronoi diagrams are widely studied and there are optimal algorithms for that. But I could not find anything on Weighted furthest point voronoi diagrams !! But ...
12
votes
1answer
274 views

Optimal randomized comparison sorting

So we all know the comparison-tree lower bound of $\lceil\log_2 n!\rceil$ on the worst-case number of comparisons made by a (deterministic) comparison sorting algorithm. It does not apply to ...
10
votes
2answers
249 views

Minimum Tree-width of circuit for MAJORITY

What is the minimum tree-width of a circuit over $\{\wedge,\vee,\neg\}$ for computing MAJ? Here MAJ $:\{0,1\}^n \rightarrow \{0,1\}$ outputs 1 iff at least half of its inputs are $1$. I care ...
0
votes
1answer
59 views

Talk for K-12 Students + General Audience Reference Request

I will be giving talks about general topics in CS, and want to hit on TCS as well. The talks will be given to K-12 schools, so not all of them will be seniors who may go to an undergraduate program at ...
8
votes
0answers
271 views

Is it possible to solve perfect matching in linear time

As we know matching can be solve in polynomial time. One classical and famous algorithm is designed by Karp and Hopcroft. Is it possible to solve perfect matching problem in linear time for given ...
9
votes
1answer
80 views

First order satisfiability that doesn't have finite models

We know from Church's theorem that determining first order satisfiability is undecidable in general, but there are several techniques we can use to determine first order satisfiability. The most ...
7
votes
2answers
149 views

Implementation of surreal numbers for games

There is a very nice construction by Conway of surreal numbers. They are "numbers" that contain both real numbers and ordinals, are totally ordered, and have all the properties of a field (except they ...
8
votes
0answers
76 views

References for de-amortization

I've been interested in looking into the area of de-amortization recently (i.e. finding data structures with matching worst-case and amortized running time bounds, or exhibiting lower bounds against ...
1
vote
0answers
84 views

Strong Dependence

I asked this question on MO, but no answer. I don't know if this definition has been already given. Suppose $X$ and $Y$ are two random variables over finite alphabets $\mathcal{X}$ and ...
5
votes
1answer
110 views

Ref question: K-nearest neighbours in a graph

Given an undirected graph $G$ with $n$ vertices, $m$ edges, and positive weights on the edges, I am interested in the problem of computing for each vertex the $k$ distinct vertices in $G$ that are ...
0
votes
0answers
131 views

Problems which are solvable using Linear Programming

Can anyone share a link to a good survey/book about the different problem types for which we have a linear programming based solution for, as well as the related techniques?
3
votes
0answers
111 views

Restricted-Input Automaton

In the classic setting, an automaton for a language $L$ is required to accept all words in $L$ and reject/get stuck on every word in $\Sigma^*\setminus L$. All of the related concepts are then ...
2
votes
0answers
63 views

efficient data structures for generalized tensor products

The usual tensor product of vectors is a matrix. There has been tons of research into efficiently storing and operating on matrices in computers. But we can generalize the tensor product quite a ...
11
votes
0answers
142 views

Lower bounds for the size of nondeterministic circuits

It is known that the minimum size of $U_2$-circuits computing the parity function exactly equals $3(n-1)$. The lower bound proof is based on the gate elimination method. Recently, I noticed that the ...
-1
votes
2answers
77 views

Arrangements of Objects

Suppose there are $n$ bins each having $k$ objects. Assume that capacity of each bin is also $k$. Now we want to rearrange the objects such that each bin contains $k$ objects but this time if $x,y$ ...
8
votes
1answer
350 views

Problem that is in P only if P!=NP

Are there any problems that are solvable in polynomial time only if P!=NP, and otherwise solvable in (say) $O(2^n)$ time? A simple example would be: If P!=NP, compute a primality test for a random ...
13
votes
1answer
448 views

The complexity of counting simple paths in a directed graph

Let $G$ be a digraph (not necessarily a DAG) and let $s,t \in V(G)$. What is the complexity of counting the number of simple $s-t$ paths in $G$. I would expect the problem to be #${\mathsf ...
6
votes
1answer
215 views
0
votes
0answers
123 views

proving speedup phenomenon does not apply to any open complexity class separations

Aaronson recently wrote a blog refuting the idea that there could be some "glitch" in the formulation of the P vs NP conjecture[1] which reminds me of this following question. the Blum speedup ...
1
vote
0answers
88 views

How to define deep learning? [closed]

Ive read some articles about deep learning but I found its hard to provide a clear definition of deep learning. For me its like an intelligent feature selection method. But it seems that its not ...
2
votes
0answers
64 views

Which paper to cite when referring to reservoir sampling *with replacement*?

As far as I can tell, the term "reservoir sampling" is commonly used to refer to sampling without replacement and references [1], [2], and [3] are cited while mentioning it. When referring to ...
7
votes
0answers
88 views

Computing the most likely winner in elections : intermediate case between Kemeny and Borda?

Given $n$ possible alternatives satisfying some unknown linear ordering, a multiset of pairwise votes, i.e., a matrix $M\in\mathbb{N}^{n\times n}$: $M_{i,j}$ counts the number of votes for which ...
5
votes
1answer
131 views

What language $L \in NCM$ has $\overline{L} \not \in NCM$?

$NCM$, the class of non-deterministic reversal-bounded counter machines, has a lot of interesting dependability and closure properties. It's known that, unlike the deterministic version, NCM is not ...
3
votes
0answers
79 views

extracting/ exploiting similarity of SAT instances by solver

suppose that two SAT formulas on different variables $F_1, F_2$ are given on the input that are known to be true and the problem is to build an algorithm that finds a solution to each. the formulas ...
6
votes
1answer
271 views

Describing state machines mathematically

The short paper "Computer Science and State Machines" by Leslie Lamport seems quite strange to me. On the one hand, I am surprised to see that an important hardware protocol called "two-phase ...
1
vote
0answers
124 views

Definition of Planar 3-SAT

What is the standard definition of Planar 3-SAT? I have seen a number of different definitions. What was the original paper that defined it and proved it to be NP-complete?
4
votes
1answer
252 views

Hardness of UNAMBIGUOUS-3DM

Let UNAMBIGUOUS-3DM be defined by analogy to UNAMBIGUOUS-SAT, i.e. as a promise problem version of three-dimensional matching where we may assume there is no more than one solution. Is there a ...
2
votes
1answer
87 views

Resource listing models with known VC dimension

Is there any reference resource gathering models with known VC dimension? I am looking for an exhaustive list of models with their VC dimension (and ideally the associated proof or a pointer to it). ...
13
votes
0answers
283 views

How can one find the “hard” probability distribution on the input for recursive boolean functions?

Update: Since, it seems there is no progress regarding this question, any idea, conjecture, hunch, or advice is welcome. For example, are there any partial or incomplete results? What are the main ...
3
votes
0answers
73 views

minimal languages that “cover” grammar productions

this question is based on generalizing two somewhat similar questions that recently appeared on the "sister" beta site cs.se (now with more questions than this one!) and which seems theoretically ...
0
votes
0answers
76 views

Graph database indexing

Graph databases are usually defined as index-free adjacency and that applies mostly to many current implementations - for example Neo4j - My question is: Is there are any references or papers with ...
6
votes
0answers
45 views

Explicit error bounds on the abelian hidden subgroup problem

What are some explicit forms for the error probability in the typical quantum abelian hidden subgroup algorithm as a function of oracles queries? Ettinger, Hoyer, and Knill give a result that the ...
19
votes
0answers
311 views

$RL=L$ Progress Since 2006

Reingold, Trevisan, and Vadhan's breakthrough 2006 paper (http://dl.acm.org/citation.cfm?id=1132583) reduced the problem of showing $RL=L$ to producing pseudorandom walks on regular digraphs that are ...
7
votes
0answers
149 views

Gaussian elimination for inverting matrices modulo prime power

Can I use Gaussian elimination to compute matrix inverse over the ring $\mathbb{Z}_{p^k}$ (ring of residues modulo $p^k$) where $p$ is prime and $k$ is an integer greater than $1$? Such matrix is ...
3
votes
1answer
86 views

any relation/ overlap between small world graphs, scale free graphs, and expander graphs?

small world graphs (eg Watts-Strogatz model & others) and scale free graphs are a relatively recently discovered graph type via mainly empirical analysis of large real-world graphs (eg via Big ...
12
votes
1answer
613 views

A course for learning algebraic complexity

I want to learn about algebraic algorithms and complexity thoery. In particular, I am interested in PIT. Is there a set of lecture notes, books, papers and surveys for students who have read standard ...
4
votes
1answer
198 views

What characterizations exist for the grammars that can express subsets of the context-free languages?

It is well known that CFGs and PDAs are equivalent, and there has been extensive research about the relationship between deterministic pushdowns and $LR(1)$ grammars, as $DCFL$ is a subset of $LR(1)$. ...
6
votes
2answers
104 views

Are deterministic context-free languages closed under outfix (or other erasing operations)

Define the outfix of a language $L$ to be $Outf(L) = \{xy \mid \exists z. xzy \in L \}$. Are any known results about whether deterministic context-free languages are closed under this operation, or ...
1
vote
0answers
68 views

Proof of convergence of alternative minimization/maximization [duplicate]

Given a problem \begin{equation} \max_{x\in X} \min_{y \in Y} f(x,y) \end{equation} where $f$ is strongly convex in $Y$ and strongly concave in $X$ How to show that the following iterative ...
0
votes
0answers
79 views

Regularlity lemma and exceptional set

Regularity lemma is one of the most basic tools in algorithmic thoery and pure math theory like additive number theory and combinatorics. This lemma is stated two ways: the existence of a partion ...
5
votes
0answers
97 views

Spectrum of absorbing random walk for regular graphs

I have a symmetric Markov chain given by the matrix $P$. Let $M$ be a set of special states of the chain (called marked states, they correspond to solutions to some problem). We can write $P$ as ...
3
votes
0answers
70 views

Probability distributions and computational complexity

Some probability distributions are easier to work with than others. Consider the following two problems. Given a number $n$, return $i$ with $0 \leq i < n$ with uniform probability, i.e. ...
6
votes
0answers
85 views

What is known about reduction by “$P_1$ interprets $P_2$” for generalized programming languages?

Inspired by this answer, let's say that a programming language is given by the data $L=(P,ev)$ where $P$ (the set of "valid programs") is a computable subset of $\Sigma^*$ and $ev$ (the "evaluator") ...