Displaying similar documents to “A remark on Abhyankar's space lines”

Wild Multidegrees of the Form (d,d₂,d₃) for Fixed d ≥ 3

Marek Karaś, Jakub Zygadło (2012)

Bulletin of the Polish Academy of Sciences. Mathematics

Similarity:

Let d be any integer greater than or equal to 3. We show that the intersection of the set mdeg(Aut(ℂ³))∖ mdeg(Tame(ℂ³)) with {(d₁,d₂,d₃) ∈ (ℕ ₊)³: d = d₁ ≤ d₂≤ d₃} has infinitely many elements, where mdeg h = (deg h₁,...,deg hₙ) denotes the multidegree of a polynomial mapping h = (h₁,...,hₙ): ℂⁿ → ℂⁿ. In other words, we show that there are infinitely many wild multidegrees of the form (d,d₂,d₃), with fixed d ≥ 3 and d ≤ d₂ ≤ d₃, where a sequence (d₁,...,dₙ)∈ ℕ ⁿ is a wild multidegree...

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

Arno van den Essen (2004)

Colloquium Mathematicae

Similarity:

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

Similarity:

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

Similarity:

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,...

The Double Tangency Symmetries in Laguerre Plane

Jarosław Kosiorek, Andrzej Matraś (2007)

Bulletin of the Polish Academy of Sciences. Mathematics

Similarity:

The group generated by double tangency symmetries in a Laguerre plane is investigated. The geometric classification of involutions of a symmetric Laguerre plane is given. We introduce the notion of projective automorphisms using the double tangency and parallel perspectivities. We give the description of the groups of projective automorphisms and automorphisms generated by double tangency symmetries as subgroups of the group M(𝔽,ℝ) of automorphisms of a chain geometry Σ(𝔽,ℝ) following...