2 8 Ju n 20 06 Discrete Math . , in press . On the unique representability of spikes over prime fields
نویسنده
چکیده
For an integer n ≥ 3, a rank-n matroid is called an n-spike if it consists of n three-point lines through a common point such that, for all k ∈ {1, 2, . . . , n− 1}, the union of every set of k of these lines has rank k + 1. Spikes are very special and important in matroid theory. Wu [13] found the exact numbers of n-spikes over fields with 2, 3, 4, 5, 7 elements, and the asymptotic values for larger finite fields. In this paper, we prove that, for each prime number p, a GF (p) representable n-spikeM is only representable on fields with characteristic p provided that n ≥ 2p− 1. Moreover, M is uniquely representable over GF (p).
منابع مشابه
On the unique representability of spikes over prime fields
For an integer n ≥ 3, a rank-n matroid is called an n-spike if it consists of n three-point lines through a common point such that, for all k ∈ {1, 2, . . . , n− 1}, the union of every set of k of these lines has rank k + 1. Spikes are very special and important in matroid theory. Wu [13] found the exact numbers of n-spikes over fields with 2, 3, 4, 5, 7 elements, and the asymptotic values for ...
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