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In mathematics, the Hermite constant, named after Charles Hermite, determines how short an element of a lattice in Euclidean space can be. The constant for integers ''n'' > 0 is defined as follows. For a lattice ''L'' in Euclidean space R''n'' unit covolume, i.e. vol(R''n''/''L'') = 1, let λ1(''L'') denote the least length of a nonzero element of ''L''. Then is the maximum of λ1(''L'') over all such lattices ''L''. The square root in the definition of the Hermite constant is a matter of historical convention. With the definition as stated, it turns out that the Hermite constant grows linearly in ''n''. Alternatively, the Hermite constant can be defined as the square of the maximal systole of a flat ''n''-dimensional torus of unit volume. ==Example== The Hermite constant is known in dimensions 1–8 and 24. For ''n'' = 2, one has . This value is attained by the hexagonal lattice of the Eisenstein integers.〔Cassels (1971) p. 36〕 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Hermite constant」の詳細全文を読む スポンサード リンク
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