Grothendieck's standard conjectures

Let YY be a smooth projective variety of dimension dYd_Y over a field kk, let HH^* be a Weil cohomology, and let Halg2j(Y)H2j(Y)H^{2j}_{\operatorname{alg}}(Y) \subset H^{2j}(Y) denote the image of the cycle class map CHj(Y)H2j(Y)CH^j(Y) \to H^{2j}(Y). For an ample divisor hPic(Y)h \in \operatorname{Pic}(Y), write

Lhj:=hj:Hj(Y)H2dYj(Y).L_h^j:=\cdot h^j:H^j(Y)\to H^{2d_Y-j}(Y).

Let δj\delta_j denote the Künneth components of the diagonal in

ΔYH2dY(Y×Y)j=02dYHj(Y)H2dYj(Y).\Delta_Y\in H^{2d_Y}(Y\times Y)\cong\bigoplus_{j=0}^{2d_Y}H^j(Y)\otimes H^{2d_Y-j}(Y).

Grothendieck's standard conjectures. The following assertions hold: (1) there exist correspondences ΛjCHj(Y×Y)\Lambda_j\in CH^j(Y\times Y) such that Λj:H2dYj(Y)Hj(Y)\Lambda_{j*}:H^{2d_Y-j}(Y)\to H^j(Y) is the inverse of LhjL_h^j; (2) every Künneth component δj\delta_j is induced by an algebraic cycle, equivalently δjHalg2dY(Y×Y)\delta_j\in H^{2d_Y}_{\operatorname{alg}}(Y\times Y); and (3), for every γHalg2j(Y)\gamma\in H^{2j}_{\operatorname{alg}}(Y), if γγ=0\gamma\cdot\gamma'=0 for all γHalg2(dYj)(Y)\gamma'\in H^{2(d_Y-j)}_{\operatorname{alg}}(Y), then γ=0\gamma=0.

These are Grothendieck's standard conjectures: the Lefschetz standard conjecture, the Künneth standard conjecture, and the assertion that numerical and homological equivalence coincide on algebraic cohomology classes. The paper's abstract states that it proves them for the Fano variety of lines on a smooth cubic hypersurface, but the supplied text does not specify which of the assertions is being proved or provide a resolution status for the general formulation.

Sources & referencesView supporting material

Primary source

Humberto A. Diaz, “The standard conjectures for the variety of lines on a cubic hypersurface”, arXiv:1706.06683 (2017).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.