Formal scheme
= Formal scheme
{wiki}
A <formal scheme> is a <locally ringed space> with a <sheaf of topological rings> that is locally a <formal spectrum> of a complete adic <ring>. An ordinary <scheme> is the special case of the discrete topology. A <formal completion of a scheme> retains all <infinitesimal neighbourhoods> of a <closed subscheme>, rather than just that subscheme.
// Target: ringed-space.bigb