Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

The Joke

The comic presents a "Mathematical Fun Fact" claiming that for each of the infinite possible espresso-to-milk ratios, there exists at least one Italian-sounding name. It shows a number line ranging from "Just Milk" on the left to "Just Espresso" on the right. Familiar real drinks are plotted at rational ratios: 1:3 "Latte," 1:2 "Cappuccino," 1:1 "Antoccino," 2:1 "Macchiato," 3:1 "Antilatte." But then the comic extends into absurd mathematical territory below the line: 1:c-squared is a "Relativisto," the golden ratio of espresso-to-milk is a "Phicetto," i:1 (using imaginary numbers) is an "Imaginarati," pi:1 is an "Irratiognito," 6.022x10^23:1 is an "Avogadro," and the limit as milk approaches zero of espresso/milk is an "Infiniccino."

The Humor

The joke works by combining two areas of nerd culture: the bewildering proliferation of Italian coffee drink names (which already feel arbitrary to many people) and mathematics. The comic's fake theorem -- that the Italian naming scheme is dense enough to cover every real (and even complex or transcendental) number -- is a parody of mathematical completeness and density theorems. Each invented name is a portmanteau blending a mathematical concept with Italian coffee nomenclature, and each one is funnier than the last because the ratios become increasingly physically impossible. You cannot have an imaginary amount of espresso, but if you could, rest assured the Italians would have a name for it.

References

The mathematical references include: c (speed of light from Einstein's E=mc^2), phi (the golden ratio, approximately 1.618), i (the imaginary unit), pi (approximately 3.14159), Avogadro's number (6.022x10^23, the number of particles in a mole), and the concept of a limit approaching infinity. The coffee drinks referenced (latte, cappuccino, macchiato) are real Italian espresso beverages distinguished primarily by their espresso-to-milk ratios.