The work of IFIP Working Group 2.1 focuses on approaches to system development that guarantee that the systems developed are "correct by construction".

Usually, the source system is a formal specification, which is transformed or refined to the target system by a sequence of meaning-preserving steps. The target systems are primarily, but not necessarily, software. They can be algorithms, distributed systems, protocols, software architectures, hybrid systems, and so on.

We are interested in languages, formalisms, theories and methods (including support tools) with a solid mathematical underpinning that can help advance the state of the art. In particular, we want to increase both the elegance and the scope of our methods.


The meetings of the Working Group provide a medium for active researchers in this area, from all over the world, for "comparing notes", exchanging not only results but also new problems or challenges in a concentrated yet highly informal atmosphere.

Next to the members, participation is only open to invited observers. Observers are invited on the basis of the perceived potential relevance of their work to the concerns of the Working Group. Contrary to what the term might suggest, observers are not supposed to just sit in on the meetings and `observe'. On the contrary, they are encouraged to participate actively in discussions and presentations alike.


At scientific conferences, presentations are supposed to present a finished and well-rounded result, with emphasis on how this improves on older results, while studiously avoiding technical detail. In strong contrast, presentations at WG2.1 meetings are more about "work in progress", and it is perfectly OK to present half-baked or even raw ideas, provided that they are sufficiently inspiring.

Of course, a good talk on finished work that is in the heart of the Working Group's concerns is also welcome. But whether the topic of a presentation is a formalism, a theorem, a new derivation or anything else, the technical details and assumptions must be out in the open, with precise definitions, so that all participants can follow and understand all steps. After all, we are a group of active researchers, and how a particular result was obtained, what reasoning led to a claim, or what motivated an approach, is often as interesting to us as the result, claim or approach itself.

In any case, it is a well-established fact that any statement, term or symbol uttered by a speaker or shown on a slide at a WG2.1 meeting, unless its meaning is crystal-clear, will prompt some member to interrupt the speaker and ask for elucidation. This behaviour, annoying as it may seem to the interruptee, is surely informed by the interrupter's ardent desire to fully understand and absorb the content of the talk. (It has not been unheard of that a speaker needed a full half hour just to proceed through the interruptions from the first to the second slide. Being precise\x97without being pedantic\x97can considerably speed up a presentation for this Group.)

From time to time a talk may prompt an impromptu discussion between the attendants, thus suspending the orderly progress of the presentation. Generally the chair will allow this as long as the discussion is germane to the higher purposes of the Working Group, but cut it short when it threatens to become repetitive or pointless.


Also very much unlike what is usual in scientific conferences, there is no fixed duration for presentations; talks simply run as long as they need and as long as there is sufficient interest, whichever of the two is shortest. The chair will cut off talks in which there is insufficient interest, an event that may transpire after five hours or after five minutes. Since the Rome meeting in 2012 we do try to keep presenters to the time they propose, interruptions and questions not counted.

Clearly, under such a regime there can be no fixed schedule for presentations. At all times there is a tentative schedule, which is continually subject to dynamic rescheduling. To compound the complexity of the problem, the Working Group welcomes impromptu presentations, usually of the nature of presenting a solution to an open problem of a previous speaker, or a substantive improvement on her or his approach.

The initial tentative schedule is drawn up using an interesting procedure that we are continuing to evolve and refine, even though it has no clearly defined effect on the actual proceedings, as there is no guarantee that talks put on the initial schedule will ever have a chance to actualize. The meeting commences with each attendee introducing themselves (name, affiliation, research interests), and, optionally, a sales pitch of up to 10 minutes in length, of the presentation(s) that person would be willing to give, together with an estimate of how much time they require for the full-length presentation(s). Alternatively, attendees might consider 10 minutes sufficient to get their ideas, or problem they want to discuss or work on, across, and leave it at this 10 minute presentation. Once everyone has introduced themselves, and their potential presentations (if any), the participants get to vote on which presentations they wish to hear, and which they do not wish to hear. These lists are used to determine whether or not a presentation should be included in the initial schedule, and how much time is likely to be allowed to it. This initial schedule is subject to revision as the meeting progresses.

Invited observers are exempted from the obligation to advertise a talk: we will make sure all invited observers will get a chance to present their work. Because of the rather dynamic schedule, we expect observers to have their talks ready when they arrive.

Since the Ottawa meeting we set aside one or two sessions in which groups of people can work together on problems. These may be problems people propose to work on during the introductions, problems that arose during a presentation, or anything else.

-- JohanJeuring - 12 Oct 2012
Topic revision: r4 - 17 Jun 2016, LambertMeertens
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