``Presentational"/graphical criterium:
- it constitutes a test for
the assignement of the values common and proper:
proper nouns are capitalized. Note that not all the capitalized nouns
are proper nouns: hence, the criterium is necessary but not sufficient.
Syntactic criterium:
- the presence/absence of the article is useful to choose between
common and proper.
Anthroponyms and nouns of cities are, in general,
incompatible with articles, Pisa, Giovanni, Laura, Roma.
Exceptions: in some uses, feminine proper first and last names can be
preceded
by the article: la Monica, i Rossi (this last to indicate the members of the
family).
Furthermore, geographic nouns, e.g. river, mountain, country nouns,
admit the presence of the article,
gli Appennini, il Tevere, l'America, i Balcani, le Alpi and also
the names of companies, even if abbreviated,
la FIAT, l'IBM, la Galileo.
This criterium is, hence, not
sufficient.