V rabote rassmatrivayutsya trekhmernye gruppy Li, privedeny razlichye klassifikatsii i sootvetstviya mezhdu nimi. Privedeny osnovnye opredeleniya i vychislitelnye formuly. Na kazhdoy gruppe postroena kontaktnaya stuktura, kontaktnaya metricheskaya struktura, naydena assotsiirovannaya metrika i vychisleny ee geometricheskie kharakteristiki (tenzor Richchi, skalyarnaya i sektsionnye krivizny). Otdelno vydelen neunimodulyarnyy sluchay. V poslednikh glavakh privedeny listingi programm (Maple), neobkhodimye dlya vychisleniy geometricheskikh kharakteristik.