Nonreduced scheme
= Nonreduced scheme
A scheme is nonreduced when its structure sheaf contains a nonzero <nilpotent element>. For an affine scheme $\operatorname{Spec}(A/I)$, this is equivalent to the ideal $I$ not being radical.
= Nonreduced scheme
A scheme is nonreduced when its structure sheaf contains a nonzero <nilpotent element>. For an affine scheme $\operatorname{Spec}(A/I)$, this is equivalent to the ideal $I$ not being radical.