General elephants for threefold extremal contractions with one-dimensional fibres: exceptional case
Sbornik. Mathematics, Tome 212 (2021) no. 3, pp. 351-373
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Let $(X, C)$ be a germ of a threefold $X$ with terminal singularities along a connected reduced complete curve $C$ with a contraction $f \colon (X, C) \to (Z, o)$ such that $C = f^{-1} (o)_{\mathrm{red}}$ and $-K_X$ is $f$-ample. Assume that each irreducible component of $C$ contains at most one point of index ${>2}$. We prove that a general member $D\in |{-}K_X|$ is a normal surface with Du Val singularities.
Bibliography: 16 titles.
Keywords:
terminal singularity, extremal curve germ, flip, divisorial contraction, $\mathbb{Q}$-conic bundle.
@article{SM_2021_212_3_a6,
author = {S. Mori and Yu. G. Prokhorov},
title = {General elephants for threefold extremal contractions with one-dimensional fibres: exceptional case},
journal = {Sbornik. Mathematics},
pages = {351--373},
publisher = {mathdoc},
volume = {212},
number = {3},
year = {2021},
language = {en},
url = {http://geodesic.mathdoc.fr/item/SM_2021_212_3_a6/}
}
TY - JOUR AU - S. Mori AU - Yu. G. Prokhorov TI - General elephants for threefold extremal contractions with one-dimensional fibres: exceptional case JO - Sbornik. Mathematics PY - 2021 SP - 351 EP - 373 VL - 212 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/SM_2021_212_3_a6/ LA - en ID - SM_2021_212_3_a6 ER -
S. Mori; Yu. G. Prokhorov. General elephants for threefold extremal contractions with one-dimensional fibres: exceptional case. Sbornik. Mathematics, Tome 212 (2021) no. 3, pp. 351-373. http://geodesic.mathdoc.fr/item/SM_2021_212_3_a6/