In June 1966 Hungarian-French architect Yona Friedman traveled to Folkestone,UK to join the International Dialogue of Experimental Architecture (IDEA)— a large two-day symposium on radical experiments with architecture and urbanism. A leading figure of “prospective” international groups of architects and artists crafting techno-futurological visions of three-dimensionally expanding cities, Friedman was a natural participant in what aspired to be a convocation of “all Europe’s creative nuts.” Yet at IDEA, Friedman set aside the provocative imagery of the Ville Spatiale —the architectural rendition of his late 1950s theory for “mobile architecture," and instead presented the project through mathematical diagrams. These diagrams were part of a theory of “scientific architecture,” as he would later call it, that Friedman was developing through visiting appointments in US and Canadian research universities. While being enthusiastically received in North America, Friedman’s mathematical exposition was met with skepticism at IDEA and reviewed as a “pseudo-mathematical” and “naive” way of justifying his aesthetic preference for space-grids. This presentation follows the mathematization of Friedman’s architectural work in its transitions and translations between North American research universities and the 1960s French architectural scene. By examining how distinct epistemic cultures influenced and received Friedman’s claims to “science,” I shed light on collusions and collisions between postwar academizing tendencies in research universities and contemporaneous avant-gardist cultures of novelty and prospectiveness in architecture. I also dwell on how particular mathematical ideas allowed Friedman to negotiate a space between the “researcher” and the “artist-demiurge,” between aniconic rationality and the aesthetic consistency of his oeuvre.