It is proved that a semi-local
ring R is analytically unramified if and only if R is a subspace of a ring which is
isomorphic to a finite direct sum of semi-local Dedekind domains. Applying this, it is
proved that a local domain R is analytically irreducible if and only if R is a
subspace of a local Dedekind domain, and this is true if and only if R is a
subspace of every local domain which dominates R and which satisfies the
altitude formula relative to R. A final application proves that an analytically
unramified local domain is unmixed if and only if it satisfies the altitude
formula.