Linked Questions

172 votes
36 answers
35k views

Proposals for polymath projects

Background Polymath projects are a form of open Internet collaboration aimed towards a major mathematical goal, usually to settle a major mathematical problem. This is a concept introduced in 2009 by ...
72 votes
3 answers
8k views

Can you solve the listed smallest open Diophantine equations?

In 2018, Zidane asked What is the smallest unsolved Diophantine equation? The suggested way to measure size is substitute 2 instead of all variables, absolute values instead of all coefficients, and ...
Bogdan Grechuk's user avatar
5 votes
5 answers
896 views

What are the integer solutions to $z^2-y^2z+x^3=0$?

The question is to describe ALL integer solutions to the equation in the title. Of course, polynomial parametrization of all solutions would be ideal, but answers in many other formats are possible. ...
Bogdan Grechuk's user avatar
24 votes
2 answers
1k views

On the smallest open Diophantine equations: beyond Hilbert's 10 problem

In 2018, Zidane asked What is the smallest unsolved Diophantine equation? The suggested way to measure size of the equation is substitute 2 instead of all variables, absolute values instead of all ...
Bogdan Grechuk's user avatar
15 votes
1 answer
4k views

Most wanted Diophantine equations

For most of my life, one single (family of) Diophantine equation(s) dominated the list of the world's most celebrated unsolved mathematical problems. Perhaps the world we live in now has grown too ...
8 votes
1 answer
639 views

On Markoff-type diophantine equation

Do there exist integers $x,y,z$ such that $$ x^2+y^2-z^2 = xyz -2 \quad ? $$ Why this is interesting? First, this equation arose in an answer to the previous Mathoverflow question What is the smallest ...
Bogdan's user avatar
  • 781
6 votes
1 answer
438 views

$y^3 = x^4 + x + 2$, and existence of rational points on rank 0 Picard curves

Do there exists rational numbers $x$ and $y$ such that $$ y^3 = x^4 + x + 2 ? $$ Context: There are a lot of publications about computing rational points on elliptic and hyperelliptic curves, and ...
Bogdan Grechuk's user avatar
4 votes
1 answer
408 views

Are these equations solvable in positive integers?

By Matiyasevich theorem, there is no algorithm to decide whether a given Diophantine equation $P(x_1,\dots, x_n)=0$ has a solution in positive integers. As suggested in What is the smallest unsolved ...
Bogdan Grechuk's user avatar
6 votes
1 answer
1k views

Find all integer solutions to the following easy-looking Diophantine equations

In general, it is not clear What does it mean to solve an equation? in integers. In this question, let us assume that an equation $$ P(x_1,\dots,x_n)=0 $$ is solved if we have proved that its integer ...
Bogdan Grechuk's user avatar
0 votes
0 answers
536 views

How to describe all integer solutions to $x^2+y^2=z^3+1$?

The question is to find all integer solutions to the equation $$ x^2+y^2=z^3+1. $$ This equation obviously has infinitely many integer solutions (take, for example, $(x,y,z)=(1,u^3,u^2)$ for any ...
Bogdan Grechuk's user avatar
5 votes
3 answers
606 views

Can you describe all rational solutions to these simple-looking equations?

Can you describe, in parametric form or in any other explicit way, all rational solutions to any of the following equations: $$ y^2 + z^2 = x^3+1, $$ $$ y^2 + z^2 = x^3-1, $$ $$ y^2+x^2y+z^2+1=0. $$ ...
Bogdan Grechuk's user avatar
7 votes
0 answers
274 views

Is decidability reducible to unique decidability (perhaps in multilinear polynomial situations)?

Given a Diophantine equation it is not decidable if it has integer solution. I. Is there a Diophantine set $\mathcal D_{unique}$ satisfying the properties every member in $\mathcal D_{unique}$ is a ...
Turbo's user avatar
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