We state and prove various new identities involving the Z(K) parafermi
on characters (or level-K string functions) c(n)l for the cases K = 4,
K = 8, and K = 16. These identities fall into three classes: identiti
es in the first class are generalizations of the famous Jacobi theta-f
unction identity (which is the K = 2 special case), identities in anot
her class relate the level K > 2 characters to the Dedekind eta-functi
on, and identities in a third class relate the K > 2 characters to the
Jacobi theta-functions. These identities play a crucial role in the i
nterpretation of fractional superstring spectra by indicating spacetim
e supersymmetry and aiding in the identification of the spacetime spin
and statistics of fractional superstring states.