Browsing Mathematics Theses and Dissertations by Author "Fisette, Robert"
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Fisette, Robert (University of Oregon, 2012)[more][less]Polishchuk, Alexander Fisette, Robert Fisette, Robert 20121026T03:58:22Z 20121026T03:58:22Z 2012 http://hdl.handle.net/1794/12368 We choose a generator G of the derived category of coherent sheaves on a smooth curve X of genus g which corresponds to a choice of g distinguished points P1, . . . , Pg on X. We compute the Hochschild cohomology of the algebra B = Ext (G,G) in certain internal degrees relevant to extending the associative algebra structure on B to an A1structure, which demonstrates that A1structures on B are finitely determined for curves of arbitrary genus. When the curve is taken over C and g = 1, we amend an explicit A1structure on B computed by Polishchuk so that the higher products m6 and m8 become Hochschild cocycles. We use the cohomology classes of m6 and m8 to recover the jinvariant of the curve. When g 2, we use Massey products in Db(X) to show that in the A1structure on B, m3 is homotopic to 0 if and only if X is hyperelliptic and P1, . . . , Pg are chosen to be Weierstrass points. iv en_US University of Oregon All Rights Reserved. Ainfinity Curve Elliptic curve Hochschild cohomology jinvariant The Ainfinity Algebra of a Curve and the Jinvariant Electronic Thesis or Dissertation
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