Search results for " 14R25"

showing 3 items of 3 documents

Algebraic models of the Euclidean plane

2018

We introduce a new invariant, the real (logarithmic)-Kodaira dimension, that allows to distinguish smooth real algebraic surfaces up to birational diffeomorphism. As an application, we construct infinite families of smooth rational real algebraic surfaces with trivial homology groups, whose real loci are diffeomorphic to $\mathbb{R}^2$, but which are pairwise not birationally diffeomorphic. There are thus infinitely many non-trivial models of the euclidean plane, contrary to the compact case.

Mathematics - Differential GeometryPure mathematicsaffine complexificationLogarithmReal algebraic model01 natural sciencesMathematics - Algebraic GeometryMathematics::Algebraic Geometry0103 physical sciencesEuclidean geometryAlgebraic surfaceaffine surfaceFOS: Mathematics0101 mathematicsInvariant (mathematics)Algebraic numberMathematics::Symplectic GeometryAlgebraic Geometry (math.AG)MathematicsAlgebra and Number Theory010102 general mathematics[MATH.MATH-AG] Mathematics [math]/Algebraic Geometry [math.AG]q-homology planesbirational diffeomorphismDifferential Geometry (math.DG)[MATH.MATH-DG]Mathematics [math]/Differential Geometry [math.DG]rational fibrationPairwise comparison010307 mathematical physicsGeometry and TopologyDiffeomorphism[MATH.MATH-AG]Mathematics [math]/Algebraic Geometry [math.AG]14R05 14R25 14E05 14P25 14J26[MATH.MATH-DG] Mathematics [math]/Differential Geometry [math.DG]Singular homology
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Algebraic models of the real affine plane

2017

We introduce a new invariant, the real (logarithmic)-Kodaira dimension, that allows to distinguish smooth real algebraic surfaces up to birational diffeomorphism. As an application, we construct infinite families of smooth rational real algebraic surfaces with trivial homology groups, whose real loci are diffeomorphic to $\mathbb{R}^2$, but which are pairwise not birationally diffeomorphic. There are thus infinitely many non-trivial models of the real affine plane, contrary to the compact case.

birational diffeomorphismaffine complexificationMathematics::Algebraic Geometry14R05 14R25 14E05 14P25 14J26.affine surface[MATH.MATH-AG] Mathematics [math]/Algebraic Geometry [math.AG]rational fibrationReal algebraic model[MATH.MATH-AG]Mathematics [math]/Algebraic Geometry [math.AG]Mathematics::Symplectic Geometry[ MATH.MATH-AG ] Mathematics [math]/Algebraic Geometry [math.AG]
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Proper triangular Ga-actions on A^4 are translations

2013

We describe the structure of geometric quotients for proper locally triangulable additve group actions on locally trivial A^3-bundles over a noetherian normal base scheme X defined over a field of characteristic 0. In the case where dim X=1, we show in particular that every such action is a translation with geometric quotient isomorphic to the total space of a vector bundle of rank 2 over X. As a consequence, every proper triangulable Ga-action on the affine four space A^4 over a field of characteristic 0 is a translation with geometric quotient isomorphic to A^3.

Algebraaffine spacesMathematics - Algebraic GeometryAlgebra and Number Theorygeometric quotientFOS: Mathematics14L30; 14R20; 14R25[MATH.MATH-AG]Mathematics [math]/Algebraic Geometry [math.AG]Algebraic Geometry (math.AG)proper additive group actionsMathematics[ MATH.MATH-AG ] Mathematics [math]/Algebraic Geometry [math.AG]
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