1,863 research outputs found

    On characteristic classes of singular hypersurfaces and involutive symmetries of the Chow group

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    For any algebraic scheme XX and every (n,L)∈ZΓ—Pic(X)(n,\mathscr{L})\in \mathbb{Z}\times \text{Pic}(X) we define an associated involution of its Chow group Aβˆ—XA_*X, and show that certain characteristic classes of (possibly singular) hypersurfaces in a smooth variety are interchanged via these involutions. For X=PNX=\mathbb{P}^N we show that such involutions are induced by involutive correspondences

    On Hirzebruch invariants of elliptic fibrations

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    We compute all Hirzebruch invariants Ο‡q\chi_q for D5D_5, E6E_6, E7E_7 and E8E_8 elliptic fibrations of every dimension. A single generating series Ο‡(t,y)\chi(t,y) is produced for each family of fibrations such that the coefficient of tkyqt^{k}y^{q} encodes Ο‡q\chi_q over a base of dimension kk, solely in terms of invariants of the base of the fibration

    On generalized Sethi-Vafa-Witten formulas

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    We present a formula for computing proper pushforwards of classes in the Chow ring of a projective bundle under the projection \pi:\Pbb(\Escr)\rightarrow B, for BB a non-singular compact complex algebraic variety of any dimension. Our formula readily produces generalizations of formulas derived by Sethi,Vafa, and Witten to compute the Euler characteristic of elliptically fibered Calabi-Yau fourfolds used for F-theory compactifications of string vacua. The utility of such a formula is illustrated through applications, such as the ability to compute the Chern numbers of any non-singular complete intersection in such a projective bundle in terms of the Chern class of a line bundle on BB

    The early poetry of W. B. Yeats

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