Real Algebraic and Analytic Geometry

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76. Jean-Yves Welschinger:
Spinor states of real rational curves in real algebraic convex $3$-manifolds and enumerative invariants.


Submission: 2004, January 6.

Let $X$ be a real algebraic convex $3$-manifold whose real part is equipped with a $Pin^-$ structure. We show that every irreducible real rational curve with non-empty real part has a canonical spinor state belonging to $\{\pm 1\}$. The main result is then that the algebraic count of the number of real irreducible rational curves in a given numerical equivalence class passing through the appropriate number of points does not depend on the choice of the real configuration of points, provided that these curves are counted with respect to their spinor states. These invariants provide lower bounds for the total number of such real rational curves independantly of the choice of the real configuration of points.

Mathematics Subject Classification (2000): 14N35, 14P25.

Keywords and Phrases: Convex manifold, real algebraic manifold, stable map, enumerative geometry.

Full text, 25p.: dvi 165k, ps.gz 270k, pdf 341k.

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