Relative effective Cartier divisor
In algebraic geometry, a relative effective Cartier divisor is roughly a family of effective Cartier divisors. Precisely, an effective Cartier divisor in a scheme X over a ring R is a closed subscheme D of X that (1) is flat over R and (2) the ideal sheaf I ( D ) {\displaystyle I(D)} of D is locally free of rank one (i.e., invertible sheaf).
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