Shokurov–Kawamata adjunction and effective adjunction conjectures

Let (T/Z,B)(T/Z,B) be a log canonical pair of dimension dd such that

KT+BR0/Z.K_T+B\sim_{\mathbb{R}}0/Z.

Define the discriminant divisor DZD_Z by

1di=sup{cKT+B+cfDi is log canonical over the generic point of Di},1-d_i=\sup\{c\mid K_T+B+cf^*D_i\text{ is log canonical over the generic point of }D_i\},

where DZ=idiDiD_Z=\sum_i d_iD_i, and define the moduli class MZM_Z, uniquely up to R\mathbb{R}-linear equivalence, by

KT+BRf(KZ+DZ+MZ).K_T+B\sim_{\mathbb{R}}f^*(K_Z+D_Z+M_Z).

Adjunction and effective adjunction conjectures. One can choose an effective representative MZ0M_Z\geq 0 in its R\mathbb{R}-linear equivalence class such that (Z,DZ+MZ)(Z,D_Z+M_Z) is log canonical. Moreover, after fixing Γf\Gamma_f, there is a constant INI\in\mathbb{N} depending only on dd and Γf\Gamma_f such that, for an appropriate choice of MZM_Z, the linear system IMZ|IM_Z| is free and

I(KT+B)fI(KZ+DZ+MZ).I(K_T+B)\sim f^*I(K_Z+D_Z+M_Z).

These assertions are general forms of the canonical bundle formula: the first gives log canonicity of the base pair, while the second predicts bounded effective representatives and an index depending only on the dimension and the specified data. They are attributed in the source to Shokurov and Kawamata and are used there as an input for boundedness arguments; no resolution status is supplied in the paper.

Sources & referencesView supporting material

Primary source

Caucher Birkar, “Boundedness of ε-log Canonical Complements on Surfaces”, arXiv:math/0409254 (2004).

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.