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Karl Schwede
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Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes (ie, $k[x,y]/(xy)$), that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particularParticularly, has it been studied before, and if so, where can I read about it?

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes (ie, $k[x,y]/(xy)$), that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particular, has it been studied before, and where can I read about it?

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes (ie, $k[x,y]/(xy)$), that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

Particularly, has it been studied before, and if so, where can I read about it?

Said more about only answering the question for nodes.
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Karl Schwede
  • 20.5k
  • 3
  • 53
  • 98

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes (ie, $k[x,y]/(xy)$), that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particular, has it been studied before, and where can I read about it?

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes, that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particular, has it been studied before, and where can I read about it?

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes (ie, $k[x,y]/(xy)$), that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particular, has it been studied before, and where can I read about it?

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Karl Schwede
  • 20.5k
  • 3
  • 53
  • 98

Tame ramification of (mild) curve singularities.

Suppose that $C$ and $D$ are curves of finite type over an algebraically closed field $k$ (we make some of these hypotheses for simplicity). We view these as pointed curves with singularities $c \in C$ and $d \in D$. I'm happy to assume that these singularities look analytically locally like $n$-coordinate-lines through the origin in $\mathbb{A}^n$; in other words $k[x_1, \dots, x_n]/(\dots, x_i x_j, \dots)$.

If you'd like to start with simple (planar) nodes, that's ok too.

Further suppose that there is a finite map $C \to D$ taking $c$ to $d$.

Question: Is there an accepted notion of what it means for such a map to have tame ramification at $d$?

And in particular, has it been studied before, and where can I read about it?