We introduce proof nets and sequent calculus for the multiplicative fragmen
t of noncommutative logic, which is an extension of both linear logic and c
yclic linear logic. The two main technical novelties are a third switching
position for the non-commutative disjunction, and the structure of order va
riety. (C) 2000 Elsevier Science B.V. All rights reserved. MSC. 03F03; 06A0
6.