David Hilbert's Problem #21

Hilbert’s Twenty-first Problem

Hilbert’s Twenty-first Problem: Proof of the existence of linear differential equations having a prescribed monodromic group

Hilbert’s 21st problem is about the existence of certain systems of differential equations with given singular points and the systems’ behavior around those points, called monodromy. Josip Plemelj published what was believed to be a solution in 1908, though much later Andrei Bolibrukh found a counterexample to Plemelj’s work, showing that such systems of equations do not have to exist.

Similar Stuff

The Formula to Get 42 Billion Digits of π

The Formula to Get 42 Billion Digits of π

While writing "7 Utterly Well-written Math Books About Pi," I found a very interesting math formula that will give you 42 consecutive digits of π accurately but is still wrong.
Black-Scholes Equation | Equations That Changed the World

Black-Scholes Equation

Black-Scholes equation says how the price of financial derivative changes over time, based on the principle that when the price is correct.
Chaos Theory | Equations That Changed the World | Abakcus

Chaos Theory

Chaos theory models how a population of living creatures changes from one generation to the next, when there are limits to the available resources. It is one of the simplest…
Information Theory| Equations That Changed the World | Abakcus

Information Theory

Information theory ushered in the age of information. It is basic to today’s digital communications—phones, CDs, DVDs, the Internet.
Schrödinger's Equation | Equations That Changed the World

Schrödinger’s Equation

Schrödinger's equation says that the equation models matter not as a particle but as a wave and describes how such a wave propagates.
Relativity | Equations That Changed the World | Abakcus

Relativity

Einstein's relativity formula says that matter contains energy equal to its mass multiplied by the square of the speed of light.
Maxwell's Equations | Equations That Changed the World | Abakcus

Maxwell’s Equations

Maxwell's equations were the first major unification of physical forces, showing that electricity and magnetism are intimately interrelated.
Navier-Stokes | Equations That Changed the World | Abakcus

Navier-Stokes

Navier-Stokes is actually Newton’s second law of motion in disguise. This formula provides an accurate way to calculate how fluids move.