LTSA - Labelled Transition System Analyser

LTSA is a verification tool for concurrent systems. It mechanically checks that the specification of a concurrent system satisfies the properties required of its behaviour. In addition, LTSA supports specification animation to facilitate interactive exploration of system behaviour.

A system in LTSA is modelled as a set of interacting finite state machines. The properties required of the system are also modelled as state machines. LTSA performs compositional reachability analysis to exhaustively search for violations of the desired properties. More formally, each component of a specification is described as a Labelled Transition System (LTS), which contains all the states a component may reach and all the transitions it may perform. However, explicit description of an LTS in terms of its states, set of action labels and transition relation is cumbersome for other than small systems. Consequently, LTSA supports a process algebra notation (FSP) for concise description of component behaviour. The tool allows the LTS corresponding to a FSP specification to be viewed graphically.

LTSA has an extensible architecture which allows extra features to be added by means of plugins.

Quick Links: [Downloads | Forum | Examples | Contacts]


Latest stable version - last updated June 2006

Eclipse Plug-in (BETA) version
  • Plug-ins currently supported (available from Eclipse installer site):
    • Message Sequence Chart plugin
    • Architecture plugin (UML2, Darwin, XADL2 etc)
    • WS-Engineer (WS-BPEL, WS-CDL, Service Modes etc)
    • SceneBeans plugin
LTSA-Delforge: extension with enhanced layout capabilities from UC Louvain


Discuss the LTSA tool and plug-ins at the LTSA Forum.


An number of examples for LTSA and plug-ins are located here.

More information

LTSA is developed by :

For more information about using LTSA and FSP, see Concurrency: State Models and Java Programs.

For technical questions about LTSA, you could try the LTSA mailing list. You can view the list archives and get details of how to subscribe (only subscribers can post to the list) here.

Last Updated: 11/11/13 (DS)