The set of unit node markers is denoted M ∩ and is the powerset 5 of M. If a unit node is marked by ∅, it is said to be generic, and the represented unit is unknown.
for a specific Lexical Unit L, (Mel'čuk, 2004, p.5) distinguishes considering L in language (i.e., in the lexicon), or in speech (i.e., in an utterance).