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suppose p:P-->XSuppose $p:P \to X$ is a projective bundle and O(1)$O(1)$ is the line bundle on P$P$ restricting to O(1)$O(1)$ on each fibre.
when When is p_*(O(1))$p_*(O(1))$ flat on X$X$?
suppose p:P-->X is a projective bundle and O(1) is the line bundle on P restricting to O(1) on each fibre.
when is p_*(O(1)) flat on X ?
Suppose $p:P \to X$ is a projective bundle and $O(1)$ is the line bundle on $P$ restricting to $O(1)$ on each fibre. When is $p_*(O(1))$ flat on $X$?
