The b-semiampleness conjecture predicts that the moduli part in the canonical bundle formula becomes a semiample divisor
on a birational model of the base and pulls back to every higher model. For a log-trivial
fibration 
,
the formula separates an adjoint pulled back from a rational line
bundle 
into a base canonical divisor, a discriminant
divisor, and a moduli part.
b-Semiampleness Conjecture
See also
b-Divisor, Canonical Bundle Formula, Canonical Divisor, Generalized Pair, Iitaka Conjecture, Kaehler Manifold, Log Calabi-Yau Pair, Log Canonical Pair, Semiample Divisor, Simple Normal Crossing DivisorExplore with Wolfram|Alpha
References
Floris, E. and Lazić, V. "A Travel Guide to the Canonical Bundle Formula." In Birational Geometry and Moduli Spaces (Ed. E. Colombo, B. Fantechi, P. Frediani, D. Iacono, and R. Pardini). Cham, Switzerland: Springer, pp. 37-55, 2020. https://doi.org/10.1007/978-3-030-37114-2_4.Cite this as:
Weisstein, Eric W. "b-Semiampleness Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/b-SemiamplenessConjecture.html