Cleo operated on Mathematics Stack Exchange from November 2013 to December 2015, posting 39 answers that primarily addressed complicated integration problems. The responses were noted for being consistently correct while providing no intermediate steps or methodological explanations, often appearing within hours of the original questions. One early example from November 11, 2013 involved a particularly difficult integral whose solution was given as I = 4π arccot(√φ), where φ is the golden ratio, with only a link defining the golden ratio and no derivation.
This image depicts the specific integral solution that Cleo provided without derivation, as discussed in the article.
This image shows the Greek letter φ used to denote the golden ratio, which appears in the integral solution mentioned in the article.
In January 2025, internet sleuths uncovered Cleo’s identity after a viewer of a YouTube video by Joe McCann traced a connection via email recovery: attempting password recovery on the Gmail account of Laila Podlesny, who had posted the integral that first brought Cleo attention, revealed a backup email matching the beginning of Vladimir Reshetnikov’s email address. When contacted, Reshetnikov confirmed he was Cleo. According to the source, he studied theoretical physics at the National University of Uzbekistan, worked as a software developer in Tashkent, and later held a position at Microsoft in the United States.
Reshetnikov explained that he created the Cleo persona to generate interest in mathematical problems that received little attention on the forum, intending the mysterious nature and terse solutions to encourage other users to develop their own problem‑solving approaches. However, the lack of explanatory detail proved controversial within the Stack Exchange community, which viewed such answers as counter to the platform’s goal of building a library of high‑quality educational content. Two days after Cleo’s answer to the notable integral, user Ron Gordon provided a detailed proof validating the solution; his explanation received over 1,000 upvotes and he was later dubbed the “Master of Integration” on the /r/math subreddit.