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  2. Quadric (algebraic geometry) - Wikipedia

    en.wikipedia.org/wiki/Quadric_(algebraic_geometry)

    The two families of lines on a smooth (split) quadric surface. In mathematics, a quadric or quadric hypersurface is the subspace of N-dimensional space defined by a polynomial equation of degree 2 over a field. Quadrics are fundamental examples in algebraic geometry. The theory is simplified by working in projective space rather than affine ...

  3. Quadric - Wikipedia

    en.wikipedia.org/wiki/Quadric

    In mathematics, a quadric or quadric surface (quadric hypersurface in higher dimensions), is a generalization of conic sections (ellipses, parabolas, and hyperbolas).It is a hypersurface (of dimension D) in a (D + 1)-dimensional space, and it is defined as the zero set of an irreducible polynomial of degree two in D + 1 variables; for example, D = 1 in the case of conic sections.

  4. Quadric geometric algebra - Wikipedia

    en.wikipedia.org/wiki/Quadric_geometric_algebra

    Representation of general quadric surfaces with useful operations will require an algebra (that appears to be unknown at this time) that extends QGA. Although rotation is generally unavailable in QGA, the transposition operation is a special-case modification of rotation by π / 2 {\displaystyle \pi /2} that works correctly on all QGA GIPNS ...

  5. Plücker coordinates - Wikipedia

    en.wikipedia.org/wiki/Plücker_coordinates

    Because they satisfy a quadratic constraint, they establish a one-to-one correspondence between the 4-dimensional space of lines in ⁠ ⁠ and points on a quadric in ⁠ ⁠ (projective 5-space). A predecessor and special case of Grassmann coordinates (which describe k -dimensional linear subspaces, or flats , in an n -dimensional Euclidean ...

  6. Analytic geometry - Wikipedia

    en.wikipedia.org/wiki/Analytic_geometry

    A quadric, or quadric surface, is a 2-dimensional surface in 3-dimensional space defined as the locus of zeros of a quadratic polynomial. In coordinates x 1 , x 2 , x 3 , the general quadric is defined by the algebraic equation [ 21 ]

  7. Fake projective plane - Wikipedia

    en.wikipedia.org/wiki/Fake_projective_plane

    A surface of general type with the same Betti numbers as a minimal surface not of general type must have the Betti numbers of either a projective plane P 2 or a quadric P 1 ×P 1. Shavel (1978) constructed some "fake quadrics": surfaces of general type with the same Betti numbers as quadrics. Beauville surfaces give further examples.

  8. Paraboloid - Wikipedia

    en.wikipedia.org/wiki/Paraboloid

    In geometry, a paraboloid is a quadric surface that has exactly one axis of symmetry and no center of symmetry. The term "paraboloid" is derived from parabola, which refers to a conic section that has a similar property of symmetry. Every plane section of a paraboloid made by a plane parallel to the axis of symmetry is a parabola.

  9. Ellipsoid - Wikipedia

    en.wikipedia.org/wiki/Ellipsoid

    An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, an ellipsoid is ...