Donald Knuth

Donald Knuth (born 1938) is professor emeritus at Stanford and among the most revered figures in computer science: author of the multi-volume “The Art of Computer Programming” (TAOCP), creator of the TeX typesetting system, and winner of the 1974 Turing Award. For half a century his standards of rigor — he famously pays bounty checks for errors found in his books — have defined what careful computer science looks like.

From “how to fake it” to “Hats off to Claude!”

In April 2023 Knuth ran a 20-question experiment on ChatGPT and was unimpressed by its confident fabrications, closing his notes with a vow to leave such research to others and devote his time to “concepts that are authentic and trustworthy.”

Three years later the concepts came to him. While preparing a TAOCP volume, Knuth posed an open problem about decomposing a directed graph into three Hamiltonian cycles. His friend Filip Stappers fed the exact wording to Claude Opus 4.6, which ran 31 explorations — brute force, serpentine patterns, fiber decompositions, simulated annealing — and produced a general construction in about an hour. Knuth wrote up the episode in a paper titled “Claude’s Cycles” (February 28, 2026, revised April 14), walking through the model’s reasoning with evident admiration and celebrating “this dramatic advance in automatic deduction and creative problem solving.”

Knuth remains a careful witness rather than a convert-evangelist: the paper documents the machine’s stumbles as faithfully as its insight. But coming from the field’s most exacting skeptic, “Hats off to Claude!” landed across computer science as a genuine turning of the page.