# Introduction

This is the web page dedicated to the tutorial presented at Petri Nets 2015 on June 23, 2015 in Bruxelles, Belgium.

# Scope

Depending on the system to model and analyse, using place/transition nets may easily be cumbersome and error-prone. Hence, it might be convenient to use some class of high-level nets. Coloured Petri nets enjoy the use of a high-level language to describe data while the net structure captures the flow of information. Although they provide very nice means for modelling, their generality has the drawback of the difficulty to apply efficient analysis techniques.

In this tutorial, we focus on symmetric nets which are high-level nets with a limited set of allowed data types, allowing for efficient state space analysis. We also tackle their extension to symmetric nets with bags for which analysis can still be applied.

The tutorial will present the underlying theory, the verification approaches, typical applications, and will put these into practice through hands-on sessions using the CosyVerif verification environment.

# Videos Online

Videos have been cut, edited and they are now online.

You can also get this tutorial on iTunes.

# Schedule

Videos of the presentation will be made available once they will be arranged (probably falls 2015).

## Session 1 : 9:30-11:00 (Slides)

**Introduction**- Petri net classes.
- Symmetric Nets (SN).

**Syntax and semantics of SN**- Syntax.
- Semantics (Firing rule).
- Reachability Graph construction.

**SN and the verification of distributed systems**- Atomic propositions.
- Reachability properties.
- Temporal properties (CTL based).

## Session 2 : 11:30-13:00 (Slides, Exercises)

- Introduction to the verification environment.
- Example in P/T and in coloured nets (the swimming pool example, maybe the fireman example too).
- Study of a simple producer/consumer system (SN).

## Session 3 : 14:30-16:00 (Slides)

**Global Symmetries vs. Local Symmetries**- Symbolic Reachability Graph (SRG)
- Extended Symbolic Reachability Graph (ESRG)
- Dynamic Symbolic Reachability Graph (DSRG)

**Symmetric nets with Bags (SNB)**- Syntactic extensions
- Semantics (Firing rule)
- «unfolding» into SN (when finite)

**Conclusion and perspectives**

## Session 4 : 16:30-18:00 (Exercises)

- Comparing the explicit approach (prod) with the SRG-based one (GreatSPN)
- Discussion of properties breaking symmetries
- Modelling in SNB: the «voter» system (simple), the «sales store system» (more complex)