Index[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] labels 2nd 3rd language constructs 2nd less than (<) let keyword lifelines communication between decomposed defined guard conditions interaction overview diagram labels and representation stacking state invariants and state variants and strict sequencing and timing diagrams and lifelines keyword local variables logical operators loop interaction operator 2nd 3rd loop nodes looping activity diagrams constraints and event occurrences 2nd interaction overview diagram lost messages 2nd |