Interaction and P systems

Interaction P Systems

S. Doumanis and A Syropoulos

Xanthi, Greece

E-mail: [email protected]

– p. 1/10

Is this the end or not?

Is the Turing machine the ultimate conceptualcomputing device?

– p. 2/10



Unless you are a Pythagorean, there is no reason toaccept the universality of the Church-Turing Thesis.

– p. 2/10




Interaction and Concurrency are more primitive thansequential reading and writing a storage medium.

– p. 2/10




Interaction and Concurrency are more primitive thansequential reading and writing a storage medium.

Interactive systems are more expressive than arbitrarysequential processes and purely functional systems.

– p. 2/10

Some thoughts on termination

Typical conceptual computing devices deliver a resultonly when they terminate.

– p. 3/10



Organisms that cease to operate do not make up asuccess story.

– p. 3/10




Modern computer based equipment that stopsoperating is considered total failure.

– p. 3/10




Modern computer based equipment that stopsoperating is considered total failure.

Only continuous operation of operating systems makesthem reliable.

– p. 3/10

Why a new variant of P systems?

P systems suffer from Turingism!

– p. 4/10



There is no agreement on the notion of success!

– p. 4/10




Typical systems do not really interact with theirenvironment!

– p. 4/10





Multiple systems do not interact with other systems byusing the environment.

– p. 4/10





Multiple systems do not interact with other systems byusing the environment.

There is no notion of history (i.e., P systems do notremember).

– p. 4/10

A New Idea

No universal clock.

– p. 5/10

A New Idea

No universal clock.

P systems should live for ever!

– p. 5/10

A New Idea

No universal clock.


Computation should be continuous, while resultsshould be partially “delivered” (think of a turnstile thatcounts people continuously).

– p. 5/10

A New Idea

No universal clock.



There should be a continuous flow of information, data,etc.

– p. 5/10

A New Idea

No universal clock.



There should be a continuous flow of information, data,etc.

Special compartments might serve ashistory-recording compartments.

– p. 5/10

Interaction multiset rewriting rules

Interaction grammars have been introduced by Wegnerto specify streams (i.e., interactive time-sensitiveanalog of strings).

– p. 6/10



Interaction multiset rewriting rules are the interactiveanalog of multiset rewriting rules.

– p. 6/10




Rules have the form α → β, where β may be formedusing the “listening” operator “.” and the“nondeterministic choice” operator “+”.

– p. 6/10




Rules have the form α → β, where β may be formedusing the “listening” operator “.” and the“nondeterministic choice” operator “+”.

The “.” operator waits for input, while the “+” operatorselect nondeterministically an event from a list of inputevents.

– p. 6/10

Interaction P System

May have initial data, but, in principle, process streamscoming from the environment.

– p. 7/10



Have a number of history compartments where datamay be stored.

– p. 7/10




At each moment t the output compartment contains apartial result.

– p. 7/10




At each moment t the output compartment contains apartial result.

The system “litters” the environment with “useless”data.

– p. 7/10

On their computational power

Remember: Interaction is more fundamental thanreading and writing to storage!

– p. 8/10



Ergo: Interaction P system ought to be moreexpressive than “conventional” P systems.

– p. 8/10



Ergo: Interaction P system ought to be moreexpressive than “conventional” P systems.

Side effect: They better model living organisms. . .

– p. 8/10

To Do List

To completely formally specify interaction P systems.

– p. 9/10

To Do List


To see for what problems they are good for.

– p. 9/10

To Do List



To use them for the simulation of living organisms.

– p. 9/10

To Do List



To use them for the simulation of living organisms.

Any suggestions?

– p. 9/10

That’s all!

Thank you for your attention!

– p. 10/10

Interaction and P systems

Science

Transcript of Interaction and P systems