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Then the intersection numbers of H and L are given by H 5 =1P, H 4 L=2P, H 3 L 2 =4P, H 2 L 3 =4P, H 1 L 4 =2P, L 5 =1P. So we have (6 H −2 E ) 5 = (2 H +2 L ) 5 = 3264 P . Fulton & MacPherson gave a precise description of exactly what "general position" means (although their two propositions about this are not quite right, and are corrected ...
One says that “the affine plane does not have a good intersection theory”, and intersection theory on non-projective varieties is much more difficult. A line on a P 1 × P 1 (which can also be interpreted as the non-singular quadric Q in P 3) has self-intersection 0, since a line can be moved off itself. (It is a ruled surface.)
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encodes all the intersection indices as its coefficients. Witten's conjecture states that the partition function Z = exp F is a τ-function for the KdV hierarchy , in other words it satisfies a certain series of partial differential equations corresponding to the basis { L − 1 , L 0 , L 1 , … } {\displaystyle \{L_{-1},L_{0},L_{1},\ldots ...
The correct number 3264 was found by Berner in 1865 and by Ernest de Jonquieres around 1859 and by Chasles in 1864 using his theory of characteristics. However these results, like many others in classical intersection theory, do not seem to have been given complete proofs until the work of Fulton and Macpherson in about 1978. Dirichlet's principle.
That is, a scheme-theoretic multiplicity of an intersection may differ from an intersection-theoretic multiplicity, the latter given by Serre's Tor formula. Solving this disparity is one of the starting points for derived algebraic geometry, which aims to introduce the notion of derived intersection.
Download as PDF; Printable version; In other projects Wikidata item; ... Pages in category "Intersection theory" The following 13 pages are in this category, out of ...
Download as PDF; Printable version; ... Intersection theory (13 P) Pages in category "Geometric intersection"