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Questions tagged [singularity-theory]

Singularities in algebraic/complex/differential geometry and analysis of ODEs/PDEs. Singular spaces, vector fields, etc.

5 questions from the last 30 days
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8 votes
1 answer
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Fibers of generic smooth maps between manifolds of equal dimension

I have heard that the following is a "well-known" Claim. Let $M$ and $N$ be smooth manifolds with equal dimensions and $M$ compact. Then a generic smooth map $f\colon M\to N$ has finite ...
Matthew Kvalheim's user avatar
2 votes
1 answer
202 views

Section 3 of Atiyah's "On analytic surfaces with double points" — some questions

I have some questions about section 3 of Atiyah's "On analytic surfaces with double points," a short 9 page paper. Section 3 is all dedicated to proving lemma 4. Near the end of section 3, ...
maxo's user avatar
  • 129
1 vote
0 answers
57 views

Discrepancy of general element of linear system

Let $X$ be a normal scheme and $|D|$ a linear system on $X$. In "Singularity of Minimal Model Program" by Janos kollar p249, it says, If $X$ is a variety over $\mathbb{C}$, and $E_j$ ...
George's user avatar
  • 328
1 vote
0 answers
85 views

Projection from a point and singularity

Let $X \subset \mathbb{P}^n$ be a hypersurface with $n \ge 3$. Let $x \in X$ be a closed point. Consider the map given by projection from $x$: $$\phi: X \dashrightarrow \mathbb{P}^{n-1}$$ Suppose that ...
Naga Venkata's user avatar
  • 1,070
0 votes
0 answers
34 views

Bôcher's theorem for singularities on the boundary

Let $\Omega\subset\mathbb{R}^2$ be connected, open, bounded, and smooth. Suppose that $u\in C^0(\bar \Omega\setminus \{0\})\cap C^2(\Omega\setminus\{0\})$ is harmonic and positive in $\Omega$. If $0\...
user128470's user avatar