In this note it will be proved that the threefold in ℂ4 which is given byx+x2y+z2+t3=0 is not isomorphic to ℂ3. Here ℂ is the field of complex numbers.

Let u be a solution of the following boundary-value problem: u¦Γ = 0, where Γ is a closed convex curve and Δu = −1 in the region D bounded by Γ. Then u has only one local maximum, and all its level… Expand

Abstract. In this paper we give a description of hypersurfaces with AK(S) = C.Let X be an aﬃne variety and let G(X) be the group generated by all C + -actions onX. Then AK(X) ⊂ O(X) is the subring of… Expand

In this note we describe the group of automorphisms of a commutative algebra with three generatorsx, y andz satisfying a relationxy= P(z), whereP(z) is a polynomial.

Bavula states [V. Bavula, The inversion formulae for automorphisms of polynomial algebras and rings of differential operators in prime characteristic, J. Pure Appl. Algebra 212 (2008), pp. 2320–2337]… Expand

— In this note I am going to generalize a theorem of J. Dixmier [1] describing the group of automorphisms of the Weyl algebra to the case of non-zero characteristic and give a new proof of it in the… Expand

Abstract We prove the Freiheitssatz for Poisson algebras in characteristic zero. We also give a new proof of the tameness of automorphisms for two generated free Poisson algebras and show that an… Expand