Resolution criteria
This is a dependent multiple-choice market: exactly one option resolves Yes; all others resolve No.
Outcome will be the top option in a separate, single-choice Manifold poll created by the market creator, closing on 31 Dec 25. The poll link will be posted in a pinned comment on this market and added here when live.
If two or more options tie for first in the poll at close, a 24-hour runoff poll among the tied options will decide the winner; this market will resolve to the runoff winner.
Background
Isaac Newton: foundational contributions to calculus, classical mechanics, and optics; Principia Mathematica (1687).
Leonhard Euler: exceptionally prolific; major results across analysis, topology, graph theory; standardized much of modern mathematical notation.
Carl Friedrich Gauss: “prince of mathematicians”; number theory, statistics, geometry, electromagnetism; Disquisitiones Arithmeticae (1801).
John von Neumann: game theory, quantum foundations, computing architecture, shock physics, numerical weather prediction.
Considerations
“Smartest” is inherently subjective; the poll operationalizes it as community judgment at a fixed time.
Cross-era comparisons are fraught: differing notation, collaboration norms, and record-keeping can bias perceptions toward prolific or recent figures.
Strong contenders beyond the listed names (e.g., Archimedes, Leonardo da Vinci, Srinivasa Ramanujan, Alan Turing) may be captured by the automatically added “Other” option.
Gauss also is differential geometry at least (theorema egregium). Euler is also an inventor of generating functions ("pentagonal theorem") and zeta function and functional analysis ("calculus of variations") and many results in number theory (proof of Fermat for 3 & 4, sum of two squares, quadratic reciprocity as a conjecture, which was proved by Gauss) and was at the start of invention of complex analysis (infinite product for sine, for instance).
Between mathematicians there are many more candidates which are imho way ahead of von Neumann: Hilbert, Poincare, Noether, Hermite, Grothendieck, Israel Gelfand.