On "full-grade", Miguel gobbles:
> That would be a silly and circular definition.
1.
http://sps.k12.mo.us/khs/linguistics/lingtrms.htm
Under the heading "ablaut":
'The Proto-Indo-European system of root vowel alternations. There
existed the following variants or "grades" of ablaut: full
(or "e") grade, full grade with ablaut (or "o"), [...]'
2.
http://www.bartleby.com/61/9.html
'Full-grade form: A form with e-vocalism (the basic form); so
identified for descriptive contrast'
3.
http://mizian.com.ne.kr/englishwiz/library/etymology/indo-european.htm
'On this basis we speak of given forms in Indo-European as
exhibiting, respectively, the e-grade (or full grade), the
o-grade, or the zero grade.'
You've been so busy reinventing your own IE that you misuse basic
terms. Perhaps you're confused with the usage of "full-grade" in a
diachronic sense when a text touches on the state of daughter languages.
So *i- _is_ zero-grade, even if there is no full-grade form of it,
because it lacks *e.
= gLeN