Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic is a "Wikipedia Tip" joke about the field of topology, a branch of mathematics concerned with properties of shapes that are preserved under continuous deformations (stretching, bending, but not tearing or gluing).

The tip reads: "Take any noun, add '(mathematics)' to it, and a topologist will manifest to write the article." Below is a mock Wikipedia article for "Crotchless pants (mathematics)." The article reads in perfectly deadpan Wikipedia style: "In mathematics, a crotchless pants is a surface which is homeomorphic to the four-holed sphere. Two pants decompositions will give two three-holed spheres, homeomorphic to crotchful pants."

The joke works on multiple levels. First, "pair of pants" is actually real mathematical terminology in topology -- a "pair of pants" (or "trinion") is a surface homeomorphic to a sphere with three holes, and "pants decompositions" are a genuine technique used in studying surfaces. So the comic takes real math jargon and extends it to its absurd logical conclusion: if mathematicians already call a three-holed sphere "pants," then surely a four-holed sphere would be "crotchless pants."

The inclusion of "Applications to String Theory" at the bottom is a recurring SMBC joke about how topology always somehow connects to string theory. The diagrams showing surfaces with holes labeled in red further sell the bit by looking exactly like real topology illustrations. The humor lies in the collision between the dry, formal tone of Wikipedia mathematics articles and the inherently ridiculous subject of "crotchless pants" as a mathematical object.