Exact m-covers and the linear form $∑^k_{s=1} x_s/n_s$

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منابع مشابه

Acta Arith. 81(1997), no. 2, 175-198. EXACT m-COVERS AND THE LINEAR FORM ∑ k s=1 xs/ns

where N is the least common multiple of those common differences (or moduli) n1, · · · , nk. For a positive integer m, (1) is said to be an m-cover of Z if its covering multiplicity is not less than m, and an exact m-cover of Z if σ(x) = m for all x ∈ Z. Note that k > m if (1) forms an m-cover of Z. Clearly the covering function σ : Z → Z is constant if and only if (1) forms an exact m-cover of...

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Let A = {as(mod ns)}s=0 be a system of residue classes. With the help of cyclotomic fields we obtain a theorem which unifies several previously known results related to the covering multiplicity of A. In particular, we show that if every integer lies in more than m0 = b ∑k s=1 1/nsc members of A, then for any a = 0, 1, 2, . . . there are at least ( m0 ba/n0c ) subsets I of {1, . . . , k} with ∑...

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CLIQUE NUMBERS OF GRAPHS AND IRREDUCIBLE EXACT m-COVERS OF Z

For each m ≥ 1, we construct a graph G = (V, E) with ω(G) = m such that max 1≤i≤k ω(G[Vi]) = m for arbitrary partition V = V1 ∪ · · · ∪ Vk, where ω(G) is the clique number of G and G[Vi] is the induced graph of Vi. Using this result, we show that for each m ≥ 2 there exists an exact m-cover of Z which is not the union of two 1-covers.

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ژورنال

عنوان ژورنال: Acta Arithmetica

سال: 1997

ISSN: 0065-1036,1730-6264

DOI: 10.4064/aa-81-2-175-198