| AGENT | A | 0 | deadlock (nil) |
| | | a.A | action prefix |
| | | A + A | (weak) choice |
| | | A | A | parallel composition |
| | | A \ a | restriction of a single action |
| | | A \ S | restriction of a set |
| | | A[R] | relabelling |
| | | (A) | you can use brackets just as you'd expect |
| | | X | agent variables begin with upper case |
| | | @ | divergence (for Walker-style divergence preorders etc.) |
| | | $ 0 | delayed nil (for TCCS) |
| | | $ a.A | delayed action prefix (for TCCS) |
| | | A ++ A | strong choice (for TCCS) |
| | | A1 : S1 | | A2 : S2 | synchronisation merge (CSP style) (S1 and S2 are action sets) |
| | | X(P,...) | parameterised agent |