138 research outputs found

    On the reducibility type of trinomials

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    Say a trinomial x^n+A x^m+B \in \Q[x] has reducibility type (n1,n2,...,nk)(n_1,n_2,...,n_k) if there exists a factorization of the trinomial into irreducible polynomials in \Q[x] of degrees n1n_1, n2n_2,...,nkn_k, ordered so that n1n2...nkn_1 \leq n_2 \leq ... \leq n_k. Specifying the reducibility type of a monic polynomial of fixed degree is equivalent to specifying rational points on an algebraic curve. When the genus of this curve is 0 or 1, there is reasonable hope that all its rational points may be described; and techniques are available that may also find all points when the genus is 2. Thus all corresponding reducibility types may be described. These low genus instances are the ones studied in this paper.Comment: to appear in Acta Arithmetic

    Smooth values of polynomials

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    Given fZ[t]f\in \mathbb{Z}[t] of positive degree, we investigate the existence of auxiliary polynomials gZ[t]g\in \mathbb{Z}[t] for which f(g(t))f(g(t)) factors as a product of polynomials of small relative degree. One consequence of this work shows that for any quadratic polynomial fZ[t]f\in\mathbb{Z}[t] and any ϵ>0\epsilon > 0, there are infinitely many nNn\in\mathbb{N} for which the largest prime factor of f(n)f(n) is no larger than nϵn^{\epsilon}

    Probabilistic Galois Theory

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    We show that there are at most On,ϵ(Hn2+2+ϵ)O_{n,\epsilon}(H^{n-2+\sqrt{2}+\epsilon}) monic integer polynomials of degree nn having height at most HH and Galois group different from the full symmetric group SnS_n, improving on the previous 1973 world record On(Hn1/2logH)O_{n}(H^{n-1/2}\log H).Comment: 10 page
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