X+Y

X+Y, released in the US as A Brilliant Young Mind, is a 2014 British drama film directed by Morgan Matthews starring Asa Butterfield, Rafe Spall, and Sally Hawkins. The film, inspired by Beautiful Young Minds, focuses on a teenage English mathematics prodigy named Nathan (Asa Butterfield) who has difficulty understanding people, but finds comfort in numbers. When he is chosen to represent Great Britain at the International Mathematical Olympiad, Nathan embarks on a journey in which he faces unexpected challenges, such as understanding the nature of love. The film premiered at the Toronto International Film Festival on 5 September 2014. The European premiere was at the BFI London Film Festival on 13 October 2014, and the UK cinema release was on 13 March 2015.

In mathematics, certain kinds of mistaken proof are often exhibited, and sometimes collected, as illustrations of a concept of mathematical fallacy. There is a distinction between a simple mistake and a mathematical fallacy in a proof: a mistake in a proof leads to an invalid proof just in the same way, but in the best-known examples of mathematical fallacies, there is some concealment in the presentation of the proof. For example, the reason validity fails may be a division by zero that is hidden by algebraic notation. There is a striking quality of the mathematical fallacy: as typically presented, it leads not only to an absurd result, but does so in a crafty or clever way. Therefore, these fallacies, for pedagogic reasons, usually take the form of spurious proofs of obvious contradictions. Although the proofs are flawed, the errors, usually by design, are comparatively subtle, or designed to show that certain steps are conditional, and should not be applied in the cases that are the exceptions to the rules.

In physics and mathematics, two-dimensional space or bi-dimensional space is a geometric model of the planar projection of the physical universe. The two dimensions are commonly called length and width. Both directions lie in the same plane.

X, Y is a 2004 independent film directed by Vladimir Vitkin.

XY or Xy may refer to:

• Xy (digraph), a digraph of the Romanized Popular Alphabet, used to write Hmong
• XY (magazine), a gay male youth magazine that also operated a personals website
• XY sex-determination system, a system in biology
• XY model, a model in physics
• coordinates, a system used to locate a point in two dimensions according to the cartesian coordinate system
• Xy, a member of the band Samael
• Aktenzeichen XY … ungelöst