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2 votes
1 answer
117 views

Blow up of terminal singularity and canonical singularity

A normal singularity $(X,x)$ over a field $k$ is terminal (resp. canonical) if $(i)$ it it is $\mathbb{Q}$-Gorenstein. and $(ii)$For any resolution of singularity $F:Y\rightarrow X$, $K_Y-f^*K_X>...
2 votes
0 answers
108 views

Finiteness of rational double point

Let $(R,\mathfrak{m })$ be a three dimensional complete local ring over a field $k$ of arbitrary characteristic and let $f\in R$ and $R/f$ is a rational double point. My question is as follows. Are ...
0 votes
0 answers
78 views

Log resolution and a divisor of pullback of function

Let $(X,x)$ be a three fold singularity $m_{X,x}$ a ideal sheaf correspoinding to $x$. $\sigma:Y_1\rightarrow X$ blow up at by $m_{X,x}$ $\phi:Y\rightarrow Y_1$ resolution of $Y_1$ Set $f:=\phi*\sigma$...
1 vote
0 answers
62 views

About the definition of cDV singularity

M. Reid defines cDV singularity as follow in his paper "CANONICAL 3-FOLDS" A point $p\in X$ of a 3-fold is called a compound Du Val point if for some section H throgh $P$, $P\in H$ is a Du ...
3 votes
1 answer
255 views

About the contractability

Let $X\subset \mathbb{P}^3$ be the surface defined by the equation $xy-zw=0$, and consider the curve $E \subset X$ defined by the equation $x=z=0$. Question. Can $E$ be contracted to a point?
2 votes
0 answers
104 views

Canonical model and the existence of general hyperplane

A variety is a separated reduced scheme of finite type over an algebraically closed field $k$ not necessarily affine. Let $X$ be a normal variety and $X$ has only one isolated singularity at $x\in X$ ...
2 votes
1 answer
133 views

A property of canonical singularity

Let $X$ be a normal variety with only one singularity at $x$ and $(X,x)$ is a canonical singularity i.e. $(X.x)$ satisfies $(i)$ and $(ii)$. $(i)$ $(X,x)$ is a $\mathbb{Q}$ Goreinstein singularity. $(...
2 votes
0 answers
95 views

Reference request The support of $f$-nef divisor

I'm seaching for a proof of the theorem below. Do you know any reference? Consider $f:X\rightarrow Y$ projective birational map between normal varieties and $\mathbb{R}$ cartier divisor $D$ whose ...