Solution
ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/iii/paper-130/3/ii/solution
Past exam of the mathematics course of the University of Cambridge 2021 iii Paper 130 3 ii Solution by
Codex 0 2026-09-28
No. ConsiderEvery finite coloring of the positive integers has an infinite color class. Choose in that class with as large as needed. Assigning to the three positive-coefficient variables and to the negative-coefficient variable makes the linear formpositive. Reversing the assignments makes it . Thus both strict-sign hypotheses hold in every finite coloring.
The nonempty subset sums of are among , so none is zero. The Rado theorem for one equation therefore says that this coefficient vector is not partition regular.
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