empty texts

is there a technique to classify empty instances (mails or articles
without any text in them at all)?

i'm having a bit of trouble getting my categorizer to recognize the
empty newspaper articles in my corpus as 'out'. it keeps classifying
them as 'con'(sumer), which is the first category in my list (and also
the first alphabetically).

will learning (training) these empty articles as 'out' help at all? so
far, it doesn't seem so.

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