Terms for Negation ?

[Stephen Hodge]

Dear Colleagues,

The general term in tradtional Sanskrit grammars for negation is, of course, 
pratiṣedha.  Due to my lack of in-depth familiarity with the traditional 
grammars, I wonder if somebody might be able to help me.  I am trying to 
find Sanskrit terms, if any, for the different sub-classes of negation, in 
particular for the various types of "a-" (for the negative of privation 
etc). All I can find are examples of about 6 sub-categories, but no 
terminology. I am trying to retrovert with a modicom of accuracy some terms 
from Tibetan. Any suggestions most welcome.

Best wishes,

Stephen Hodge