It refers to the discovery of irrational numbers (the discovery of incommensurability), which caused "logical contradictions" that many mathematicians could not explain at that time.

In the mathematics field at that time, it was a great shock, which caused the so-called first mathematics crisis.

In fact, the discovery of irrational numbers is one of the greatest achievements of Pythagoras school and an important milestone in the history of mathematics.

How was the first mathematical crisis solved?

Faced with the facts, mathematicians opened their minds and introduced "irrational numbers" into the big family of mathematics, making mathematics richer and more complete, adding irrational numbers, and finally filling up several lines, thus solving the first mathematical crisis.

Non-Euclidean geometry was born. ...