释义 |
SubspaceLet be a Real Vector Space (e.g., the real continuous functions on aClosed Interval , 2-D Euclidean Space , the twice differentiable real functions on , etc.). Then is a real Subspace of if is a Subset of and, for every , and (the Reals), and . Let be a homogeneous system of linear equations in , ..., . Then theSubset of which consists of all solutions of the system is a subspace of .
More generally, let be a Field with , where is Prime, and let denote the -DVector Space over . The number of -D linear subspaces of is
where this is the q-Binomial Coefficient (Aigner 1979, Exton 1983). The asymptotic limit is
where
(Finch). The case gives the q-Analog of the Wallis Formula.See also q-Binomial Coefficient, Subfield, Submanifold References
Aigner, M. Combinatorial Theory. New York: Springer-Verlag, 1979.Exton, H. -Hypergeometric Functions and Applications. New York: Halstead Press, 1983. Finch, S. ``Favorite Mathematical Constants.'' http://www.mathsoft.com/asolve/constant/dig/dig.html
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