Shokurov's effective log adjunction conjecture

From papers

Let (X,Δ)(X,\Delta) be a log klt pair and let f ⁣:XYf\colon X\to Y be a surjective morphism such that the Kodaira dimension of KX+ΔK_X+\Delta restricted to the general fibre is zero. Assume

KX+Δ=f(KY+BY+MY),K_X+\Delta=f^*(K_Y+B_Y+M_Y),

where BYB_Y is the discriminant divisor and MYM_Y is the moduli divisor. Shokurov's effective log adjunction conjecture. (1) There exists a birational contraction μ ⁣:YY\mu\colon Y'\to Y such that, after base change, the induced moduli divisor MYM_{Y'} on YY' is semiample. (2) If XηX_\eta is the generic fibre of ff, then

I(KXη+ΔXη)0,I(K_{X_\eta}+\Delta_{X_\eta})\sim 0,

where II depends only on dimXη\dim X_\eta and the horizontal multiplicities of Δ\Delta. (3) There exists a positive integer II depending only on the dimension of XX and the horizontal multiplicities of Δ\Delta such that IMYIM_{Y'} is base point free on some model Y/YY'/Y. These assertions concern semiampleness and effective bounds for the moduli part in the canonical bundle formula; the cited source does not provide evidence resolving them.

Progress summary

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

Sources & referencesView supporting material

Primary source

Gueorgui Todorov, “Effective log Iitaka fibrations for surfaces and threefolds”, arXiv:0805.3494 (2008).

Solutions 0

No solutions have been posted yet.