ELI5: Explain Like I'm 5

Topological Galois theory

Okay kiddo, let me explain what is topological Galois theory in a way that is easy for you to understand.

Imagine you and your friends are playing a game and you want to know if it is possible to make some changes to the game without changing its outcome. For example, if you are playing "tic-tac-toe" and you switch the positions of X's and O's but keep the same pattern, does the game still end the same way? This is what mathematicians call a "symmetry" of the game.

In the same way, mathematicians study "symmetries" of objects in mathematics. For example, think of a square. You can rotate it by 90, 180, or 270 degrees and it still looks the same. This means that the group of symmetries of a square is a group with 4 elements: identity, rotation by 90 degrees, rotation by 180 degrees, and rotation by 270 degrees. We call this group the "symmetry group" of a square.

Now, Galois theory is a branch of mathematics that studies the relationship between polynomials and their roots (solutions). For example, if you have a polynomial of degree 3, you may ask if you can find its roots using only the operations of addition, subtraction, multiplication, and division. Galois theory gives you an answer to this question.

Topological Galois theory is a way of studying the Galois theory by using topology. Topology is a branch of mathematics that studies the properties of shapes that don't change when you bend or stretch them. For example, a circle and a square are different shapes, but they have the same topology, because you can bend and stretch a circle to make a square.

In topological Galois theory, you study the symmetries of the objects that come up in Galois theory using topology. For example, if you have a polynomial of degree 3, you may ask if you can find its roots using only the operations of addition, subtraction, multiplication, and division, and taking cube roots. This gives you a group of symmetries of the roots of the polynomial, and you can study this group using topology.

Topological Galois theory is a sophisticated tool that can be used to solve many difficult problems in mathematics. It is also an active area of research, and mathematicians are always finding new ways to use it to understand the symmetries of objects in mathematics.