Mycielski's Theorem

Mycielski's theorem, in graph theory, follows from the construction Jan Mycielski introduced in 1955, known as the Mycielskian, which builds a larger graph from a given one. Applying the construction preserves the property of being triangle-free while increasing the chromatic number, so repeatedly applying it to a triangle-free starting graph shows that triangle-free graphs can have arbitrarily large chromatic numbers, the result now known as Mycielski's theorem. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/