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Let $X$ be a projective variety, $D$ be an effective divisor, suppose there exists an invertible sheaf $L$ such that $L^n=\mathcal{O}(D)$, then we could obtain a cyclic cover $p:\tilde{X}\to X$ by taking n-th root out of $D$. If we denote $G$ be the deck transformation group of this covering, then $G=\mathbb{Z}_n$. I know the paper of Pardini who generalized the construction to ramified covering with $G$ an abelian group.

My question is:

Is there any algebraic construction of a ramified covering along an effective divisor $D$ with $G=S_n$, where $S_n$ is the symmetric group for n elements?

From topological point of view, the covering with $G=S_n$ will be equivalent of existence a representation $\rho:\pi_1(X\setminus D)\to S_n$ and the kernel of this map gives a n-fold covering. However, is there a building data for such kind of $\rho$ to exists?

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  • $\begingroup$ Welcome new contributor. What kind of answer are you looking for? Do you want a description as a "flat multisection" in a rank $n$ vector bundle with an algebraically integrable connection? Do you want a description in terms of local monodromies around intersecting branches of the branch divisor that are not "too" commutative? $\endgroup$ Commented Jul 21, 2023 at 11:39

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You might have a look at

H. Tsuchihashi: Galois coverings of projective varieties for dihedral and symmetric groups, Kyushu J. Math. 57, No. 2, 411-427 (2003). ZBL1072.14018.

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