we assume these hyperplanes intersect at a unique point a

  • 1Chow ring — In algebraic geometry, the Chow ring (named after W. L. Chow) of an algebraic variety is an algebraic geometric analogue of the cohomology ring of the variety considered as a topological space: its elements are formed out of actual subvarieties… …

    Wikipedia

  • 2Cartesian coordinate system — Illustration of a Cartesian coordinate plane. Four points are marked and labeled with their coordinates: (2, 3) in green, (−3, 1) in red, (−1.5, −2.5) in blue, and the origin (0, 0) in purple. A Cartesian coordinate system specifies each point… …

    Wikipedia