enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Ptolemy's inequality - Wikipedia

    en.wikipedia.org/wiki/Ptolemy's_inequality

    For four points in order around a circle, Ptolemy's inequality becomes an equality, known as Ptolemy's theorem: ¯ ¯ + ¯ ¯ = ¯ ¯. In the inversion-based proof of Ptolemy's inequality, transforming four co-circular points by an inversion centered at one of them causes the other three to become collinear, so the triangle equality for these three points (from which Ptolemy's inequality may ...

  3. List of unsolved problems in mathematics - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    Clay Mathematics Institute: 2000 Simon problems: 15 < 12 [7] [8] Barry Simon: 2000 Unsolved Problems on Mathematics for the 21st Century [9] 22 – Jair Minoro Abe, Shotaro Tanaka: 2001 DARPA's math challenges [10] [11] 23 – DARPA: 2007 Erdős's problems [12] > 934: 617: Paul Erdős: Over six decades of Erdős' career, from the 1930s to 1990s

  4. Mathematical joke - Wikipedia

    en.wikipedia.org/wiki/Mathematical_joke

    The first part of this joke relies on the fact that the primitive (formed when finding the antiderivative) of the function 1/x is log().The second part is then based on the fact that the antiderivative is actually a class of functions, requiring the inclusion of a constant of integration, usually denoted as C—something which calculus students may forget.

  5. Order theory - Wikipedia

    en.wikipedia.org/wiki/Order_theory

    Order theory is a branch of mathematics that investigates the intuitive notion of order using binary relations.It provides a formal framework for describing statements such as "this is less than that" or "this precedes that".

  6. Cyclic group - Wikipedia

    en.wikipedia.org/wiki/Cyclic_group

    For example, Z/12Z is isomorphic to the direct product Z/3Z × Z/4Z under the isomorphism (k mod 12) → (k mod 3, k mod 4); but it is not isomorphic to Z/6Z × Z/2Z, in which every element has order at most 6. If p is a prime number, then any group with p elements is isomorphic to the simple group Z/pZ.

  7. Discriminant of an algebraic number field - Wikipedia

    en.wikipedia.org/wiki/Discriminant_of_an...

    In mathematics, the discriminant of an algebraic number field is a numerical invariant that, loosely speaking, measures the size of the (ring of integers of the) algebraic number field. More specifically, it is proportional to the squared volume of the fundamental domain of the ring of integers , and it regulates which primes are ramified .

  8. Barycentric coordinate system - Wikipedia

    en.wikipedia.org/wiki/Barycentric_coordinate_system

    Barycentric coordinates are strongly related to Cartesian coordinates and, more generally, affine coordinates.For a space of dimension n, these coordinate systems are defined relative to a point O, the origin, whose coordinates are zero, and n points , …,, whose coordinates are zero except that of index i that equals one.

  9. Self-adjoint operator - Wikipedia

    en.wikipedia.org/wiki/Self-adjoint_operator

    In mathematics, a self-adjoint operator on a complex vector space V with inner product , is a linear map A (from V to itself) that is its own adjoint. That is, A x , y = x , A y {\displaystyle \langle Ax,y\rangle =\langle x,Ay\rangle } for all x , y {\displaystyle x,y} ∊ V .