Displaying similar documents to “Wild Multidegrees of the Form (d,d₂,d₃) for Fixed d ≥ 3”

The solution of the Tame Generators Conjecture according to Shestakov and Umirbaev

Arno van den Essen (2004)

Colloquium Mathematicae

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The tame generators problem asked if every invertible polynomial map is tame, i.e. a finite composition of so-called elementary maps. Recently in [8] it was shown that the classical Nagata automorphism in dimension 3 is not tame. The proof is long and very technical. The aim of this paper is to present the main ideas of that proof.

Tame Automorphisms of ℂ³ with Multidegree of the Form (p₁,p₂,d₃)

Marek Karaś (2011)

Bulletin of the Polish Academy of Sciences. Mathematics

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Let d₃ ≥ p₂ > p₁ ≥ 3 be integers such that p₁,p₂ are prime numbers. We show that the sequence (p₁,p₂,d₃) is the multidegree of some tame automorphism of ℂ³ if and only if d₃ ∈ p₁ℕ + p₂ℕ, i.e. if and only if d₃ is a linear combination of p₁ and p₂ with coefficients in ℕ.

Multidegrees of tame automorphisms of ℂⁿ

Marek Karaś

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Let F = (F₁,...,Fₙ): ℂⁿ → ℂⁿ be a polynomial mapping. By the multidegree of F we mean mdeg F = (deg F₁, ..., deg Fₙ) ∈ ℕ ⁿ. The aim of this paper is to study the following problem (especially for n = 3): for which sequence (d₁,...,dₙ) ∈ ℕ ⁿ is there a tame automorphism F of ℂⁿ such that mdeg F = (d₁,..., dₙ)? In other words we investigate the set mdeg(Tame(ℂⁿ)), where Tame(ℂⁿ) denotes the group of tame automorphisms of ℂⁿ. Since mdeg(Tame(ℂⁿ)) is invariant under permutations of coordinates,...

On reconstruction of polynomial automorphisms

Paweł Gniadek (1996)

Annales Polonici Mathematici

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We extend results on reconstructing a polynomial automorphism from its restriction to the coordinate hyperplanes to some wider class of algebraic surfaces. We show that the algorithm proposed by M. Kwieciński in [K2] and based on Gröbner bases works also for this class of surfaces.

Polynomial automorphisms over finite fields: Mimicking tame maps by the Derksen group

Maubach, Stefan, Willems, Roel (2011)

Serdica Mathematical Journal

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2010 Mathematics Subject Classification: 14L99, 14R10, 20B27. If F is a polynomial automorphism over a finite field Fq in dimension n, then it induces a permutation pqr(F) of (Fqr)n for every r О N*. We say that F can be “mimicked” by elements of a certain group of automorphisms G if there are gr О G such that pqr(gr) = pqr(F). Derksen’s theorem in characteristic zero states that the tame automorphisms in dimension n і 3 are generated by the affine maps and the one map (x1+x22,...

Classification of degree 2 polynomial automorphisms of C.

John Erik Fornaess, He Wu (1998)

Publicacions Matemàtiques

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For the family of degree at most 2 polynomial self-maps of C3 with nowhere vanishing Jacobian determinant, we give the following classification: for any such map f, it is affinely conjugate to one of the following maps: (i) An affine automorphism; (ii) An elementary polynomial autormorphism E(x, y, z) = (P(y, z) + ax, Q(z) + by, cz + d), where P and Q are polynomials with max{deg(P), deg(Q)} = 2 and abc ≠ 0. ...

On the automorphism group of the countable dense circular order

J. K. Truss (2009)

Fundamenta Mathematicae

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Let (C,R) be the countable dense circular ordering, and G its automorphism group. It is shown that certain properties of group elements are first order definable in G, and these results are used to reconstruct C inside G, and to demonstrate that its outer automorphism group has order 2. Similar statements hold for the completion C̅.

Polynomial Automorphisms Over Finite Fields

Maubach, Stefan (2001)

Serdica Mathematical Journal

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It is shown that the invertible polynomial maps over a finite field Fq , if looked at as bijections Fn,q −→ Fn,q , give all possible bijections in the case q = 2, or q = p^r where p > 2. In the case q = 2^r where r > 1 it is shown that the tame subgroup of the invertible polynomial maps gives only the even bijections, i.e. only half the bijections. As a consequence it is shown that a set S ⊂ Fn,q can be a zero set of a coordinate if and only if #S = q^(n−1).