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Let $D$ be an effective Cartier divisor on a normal noetherian scheme $X$. Its irreducible components are codimension $1$ subschemes, i.e. Weil divisors, of $X$ but not necessarily Cartier divisors. I would like to construct a birational morphism $f:X' \to X$ such that the irreducible components of the pullback $f^*D$ are Cartier divisors. If $f$ were only an alteration, that would also be fine.

If we assume resolution of singularities, this is possible: Just choose $f$ such that $X'$ is regular. Then every Weil divisor is Cartier and we are done. Is there an argument avoiding resolution of singularities (and the theory of alterations)?

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    $\begingroup$ What about blowing up the components ? Maybe I'm being stupid since the Weil divisors are cod = 1, but.... $\endgroup$
    – meh
    Commented Apr 18, 2019 at 18:46
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    $\begingroup$ The problem is that I don't know why the exceptional divisor should be irreducible when blowing up one component. $\endgroup$ Commented Apr 18, 2019 at 20:33

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