Questions tagged [comp-number-theory]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
25
votes
2answers
946 views

Complexity of factoring in number fields

What is known about the computational complexity of factoring integers in general number fields? More specifically: Over the integers we represent integers via their binary expansions. What is the ...
20
votes
1answer
424 views

Is prime-counting function #P-complete?

Recall $\pi(n)$ the number of primes $\le n$ is the prime-counting function. By "PRIMES in P", computing $\pi(n)$ is in #P. Is the problem #P-complete? Or, perhaps, there is a complexity reason to ...
19
votes
4answers
640 views

How to obtain the unknown values $a_i,b_j$ given an unordered list of $a_i-b_j\mod N$?

Can anyone help me with the following problem? I want to find some values $a_i,b_j$ (mod $N$) where $i=1,2,…,K, j=1,2,…,K $ (for example $K=6$), given a list of $K^2$ values that correspond to the ...
18
votes
3answers
2k views

Determinant modulo m

What are the known efficient algorithms for computing a determinant of an integer matrix with coefficients in $\mathbb{Z}_m$, the ring of residues modulo $m$. The number $m$ may not be prime but ...
16
votes
1answer
551 views

$(2^n)! = \sum_{k=0}^{m-1} a_k b_k^{c_k} $?

While reading Dick Lipton's blog, I stumbled across the following fact near the end of his Bourne Factor post: If, for every $n$, there exists a relation of the form $$ (2^n)! = \sum_{k=0}^{m-1} ...
14
votes
1answer
1k views

Deciding whether an interval contains a prime number

What is the complexity of deciding whether an interval of the natural numbers contains a prime? A variant of the Sieve of Eratosthenes gives an $\tilde O(L)$ algorithm, where $L$ is the length of the ...
14
votes
1answer
710 views

Is there a quantum NC algorithm for computing GCD?

From the comments on one of my questions on MathOverflow I get the feeling that the question regarding GCD being in $\mathsf{NC}$ vs. $\mathsf{P}$ is akin to the question regarding Integer ...
13
votes
4answers
3k views

Computing the Mobius function

The Mobius function $\mu(n)$ is defined as $\mu(1)=1$, $\mu(n)=0$ if $n$ has a squared prime factor, and $\mu(p_1 \dots p_k)= (-1)^k$ if all the primes $p_1,\dots,p_k$ are different. Is it possible to ...
12
votes
0answers
265 views

Conditional density of primes

We have some theorems about the density of prime numbers, the most famous one is probably the prime number theorem. My question is about the density of primes when we choose random numbers from a ...
12
votes
1answer
826 views

Complexity class of this problem?

I am trying to understand to which complexity class the following problem belongs: Exponentiating Polynomial Root Problem (EPRP) Let $p(x)$ be a polynomial with $\deg(p) \geq 0$ with coefficients ...
11
votes
3answers
2k views

Using the de Bruijn sequence to find the $\lceil\log_2 v \rceil$ of an integer $v$

Sean Anderson published bit twiddling hacks containing the Eric Cole's algorithm to find the $\lceil\log_2 v \rceil$ of an $N$-bit integer $v$ in $O(\lg(N))$ operations with multiply and lookup. The ...
10
votes
0answers
219 views

Does a polynomial-time algorithm for factoring product of two primes imply a polynomial-time algorithm for factoring in general?

Is it known if the existence of a polynomial-time algorithm for the promise problem of factoring of numbers with two prime factors implies that factoring in general has a polynomial-time algorithm?
9
votes
2answers
311 views

Any computable transcendental number that is computable in P time but not $O(n)$

Is there any known computable transcendental number such that its $n$th digit is computable in polynomial time, but not in $O(n)$?
9
votes
1answer
309 views

Algorithm to compute distance between powers

Given coprime $a, b$, can you quickly compute $$ \min_{x, y > 0} |a^x - b^y| $$ Here $x, y$ are integers. Obviously taking $x = y = 0$ gives an uninteresting answer; in general how close can these ...
7
votes
2answers
239 views

Complexity class of phase information in Gauss sum

Have number theoretic functions such as Gauss sums been studied from a complexity view point? Where can I get a good introduction into complexity of Gauss sum estimation (beyond the quadratic case)? ...
7
votes
1answer
399 views

Discrete log in GL(2,p)

Let $p$ be a large prime. Let $A$ be a $2\times 2$ matrix with coefficients in $GF(p)$ (i.e., coefficients taken modulo $p$). Let $B=A^k$, where $k$ is an integer not given to us. Given $p$, $A$, ...
7
votes
1answer
548 views

Downward self-reducibility of factorization

Is integer factorization downward self-reducible? Is anything known about this?
7
votes
0answers
160 views

Simplified lattices

Consider the following question: Let $N$ be some large prime number, and suppose we are given $n$ uniformly independent samples $g_i$ from $0...,N-1$. Think of $N$ as being exponentially large in $n$...
6
votes
2answers
173 views

Difference Sets

Suppose we have a set $$P=\{p_1,p_2,...,p_K\}$$ where $$1\leq p_k\leq N , k=1,...,K \qquad \& \quad p_k \in \mathbb{N} $$ and $p_k$'s are distinct. We calculate the differences as: $$d=p_i-p_j\mod ...
6
votes
1answer
241 views

Integer factorization using polynomial whose roots are prime factors

Let $n$ be a square-free positive integer, let $n=p_{1}p_{2}\ldots p_{k}$ be the prime factorization of $n$ into $k$ distinct primes $p_{i}$. For such $n$, define $F_{n}(x)\triangleq\prod_{i=1}^{k}(x-...
6
votes
0answers
286 views

Is there any algorithm outputing $e$ in real time?

The Hartmanis-Stearns Conjecture says that a number computed in real time by a Turing Machine is either rational or transcendental. We know that there is some transcendental (Liouville) number that ...
5
votes
1answer
262 views

Is the primality problem with unary input NLOGSPACE-Hard?

Consider the language $L=\{1^n : n \text{ is prime}\}$. Is this language NLOGSPACE-Hard? The motivation for this question is that $L$ is a good candidate for reducing to other languages related to my ...
5
votes
0answers
93 views

How short can reversible representations of the n-bit primes be?

For $\: 1 < n \:$ and $\: n^{o(1)} < \sigma \leq n \:$, $\:$ how small can $L$ be for there to be for there to be an efficiently computable (deterministic) function $\;\; f \: : \: \{0\hspace{....
4
votes
1answer
495 views

Computational complexity of modular power towers (tetration)

The complexity of modular addition is known: $g + p \mod N$ (for $|p| \approx |g| \approx |N|$) can be computed in $O(n = |N|)$. The complexity of modular multiplication is open though some results ...
4
votes
1answer
137 views

Solving a system of sums-of-powers polynomials

What is the complexity of calculating the values of the integers $x_i$, where $0 \leq x_1 < x_2 < \dots < x_k < n$, given only the values $s_m = \sum_{i=1}^k x_i^m$? for $1 \leq m \leq k$? ...
4
votes
0answers
182 views

What is the computational complexity of Hilbert Tenth problem over $\mathbb{Q_p}$

We know that Hilbert Tenth problem over $\mathbb{Q_p}$ is decidable,so what is the computational complexity of Hilbert Tenth problem over $\mathbb{Q_p}$? Is it equivalent to Tarski elimination ...
3
votes
1answer
104 views

Complexity of higher order residues

Let $P$ be a prime. Given a number $a$, what is the computational complexity in establishing if $a$ is a cubic or higher order residue modulo $P$? Are there any good algorithms?
3
votes
0answers
75 views

How to charactorize computational complexity based on finding solution to algebraic equations? [closed]

The Matiyasevich/MRDP Theorem relates two notions:one from computability theory, the other from number theory, thus Turing Machine and algorithms finding integral solution to algebraic equations can ...
3
votes
0answers
75 views

Finding degree two subfield

Let $K=\frac{\mathbb{Q}[x]}{<f(x)>}$ where $f(x)$ is irreducible over $\mathbb{Q}$ and has even degree. I want to find $K_2$ such that $ \mathbb{Q} \subseteq K_2\subseteq K$ and $[K_2:\mathbb{Q}]...
2
votes
1answer
224 views

n irrational number whose digits are pseudo-random: conceptual mismatch?

Are there irrational numbers whose digits are considered pseudo-random? Both concepts seem to be mismatched as a pseudo-random number generator typically is periodic and therefore generates a ...
2
votes
1answer
159 views

Is there a fast algorithm to quickly evaluate $a^{b^c}$ mod $n$?

I need to quickly evaluate $a^{b^c} \mod n$ where $c$ is pretty big. Using the usual repeated squaring trick, this can be performed in $O(\log(b^c)) = O(c)$ time. In my problem, $c$ is huge, (say, $&...
2
votes
0answers
104 views

What is the complexity of computation of zero point by Rieman zeta function?

What is the complexity of computation of zero point by Rieman zeta function? That is, given s, whether ζ(s)=0? Is it in P? Any reference is appreciated.
2
votes
0answers
242 views

Sieve Methods for Twin Primes - How to extract algorithm from formula

I am reading Cojocaru and Murty's Introduction to Sieve Methods and their Applications. They wait until Chapter 5 to discuss the Sieve of Eratosthenes for finding primes - and their version of it is ...
1
vote
1answer
104 views

What is necessary and/or sufficient requirement for a subring of a field to be computable? [closed]

As title asks, what is necessary and/or sufficient requirement for a subring of a field to be a computable ring? Conditions on either field or subring are fine.
1
vote
1answer
206 views

Relation between transcendental numbers and computational complexity?

Regarding the relation, there is the Hartmanis-Stearns conjecture, but beyond Turing Machine of the realtime output, there is no further conjecture or theorem. Obviously irrational algebraic number ...
1
vote
1answer
184 views

What algorithms do you know for beltway reconstruction? [closed]

I've faced the beltway reconstruction problem and I've developed a simple backtrack algorithm, what algorithms do you know for this problem? Beltway Reconstruction Problem: Assume there is a set of ...
1
vote
0answers
95 views

Fixed dimension Integer programming minus LLL in fixed parameter $NC$?

If you remove LLL part then is remaining part of a. Lenstra algorithm b. Barvinok algorithm in $O(f(n)(\log(mL))^c)$ time on $O(g(n)(mL)^c)$ processors with fixed $c>0$ in fixed $n$...
-1
votes
0answers
14 views

Least-buffer 2ᵏ→n∈⟨1;2ᵏ⟩∩ℕ base conversion of equal-probability messages source

Having an infinite source of messages of $2^k$ possible values of equal probability of occurrence, what is the least necessary buffer needed for a reversible conversion of it to a source of messages ...
-3
votes
1answer
183 views

The factoring problem reduces to order finding or is it the other way around? [closed]

initially i was not at all equipped in theoretical computer science and knew only basics of number of theory. I started working from scratch on the age old problem of primality testing which led me to ...