import unicodedata


def _token_splittable(token):
    """
    Predicate for whether a token name can be split into multiple tokens.

    A token is splittable if it does not contain an underscore character and
    it is not the name of a Greek letter. This is used to implicitly convert
    expressions like 'xyz' into 'x*y*z'.
    """
    if '_' in token:
        return False
    else:
        try:
            return not unicodedata.lookup('GREEK SMALL LETTER ' + token)
        except KeyError:
            pass
    if len(token) > 1:
        return True
    return False