A real Cartier divisor is ample if it is a positive real combination of ample Cartier divisors. Equivalently its numerical class lies in the ample cone. To recover an actual positive combination from the numerical condition, write the divisor in a finite Cartier basis and take nearby rational points in the inverse image of the open ample cone. A small rational simplex around the original coefficient vector expresses it as a positive convex combination of rational ample Cartier combinations; clearing denominators gives ample Cartier divisors.
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