## Chu Spaces

Chu Spaces are a simple and surprisingly general mathematical construct with applications to linear logic, concurrency, games, physics, philosophy and foundational mathematics. If he hasn't run across them before, I imagine (at least) Andris Birkmanis will find them quite interesting.

## Comment viewing options

### Disappointing

C'mon. "Chu Calculator?" Rather obviously, this should have been called "Chu Toy."

### Event-State Duality: The Enriched Case

If he hasn't run across them before, I imagine (at least) Andris Birkmanis will find them quite interesting.

Thank you, but I doubt this recommendation will attract many readers :-)

No, I haven't run across Chu spaces before, and today just had enough time to take a look at the introduction and one of the applications, namely Event-State Duality: The Enriched Case:

The states of a computing system bear information and change time,
while its events bear time and change information.

This view organizes states and events into two complementary spaces, state
spaces or automata and event spaces or schedules, whose distances are respectively
information deltas and time deltas. The two spaces are interderivable, and
are shaped similarly (linearly) by sequential behavior but strikingly differently
by concurrency.

This meshes well with my recent intuitions and I hope to enjoy exploring the particular application, and Chu spaces in general. Thanks again!

### Musings

The word "chu" reminds me of the word "queue". "Queue" is widely used in broarcasting with a similar meaning. "Queue the anouncer", for instance. But it is often actually computerized and automated such as roll tape five seconds befor the end of the program. The meaning is very similar. Queue generation involves gathering information and issueing a command. The command and action leads to new information, and so on. The word queue also means a line, closely related to a schedule.

### Mathematical formality

Yes, but the idea of a "chu space" would seem closely related to "queue space" a queue or a list of queues. The difference seems to be mathematical formality. A queue is sometimes used to mean an element of a queue. This seems ambiguous but it actually happens. Queues often have this meaning in broadcasting. The announcer queue defines both information and action. The person giving the "queue" has this definition as well as all the other "queues" making up the program. (ie the list of queues) or according the some the queue (ie the line or schedule of events). Oh well! Edit: an announcer queue could also be a chu. A queue is an individual member of THE queue.

### it IS a different word.

You "cue" an announcer. A show is a list of cues, or I suppose one could say a "queue of cues", but definitely not "a list of queues" as you say. The words are distinct and unrelated.

I guess I should know, I wrote the first version of a program called CueStation which is used to run the audio for many broadway shows, casinos, theme parks, cruise ships, etc.

### My point was the similarity

My point was the similarity between the concept of chu space in the above cited paper and the programming of cues (or as I said queues). Sorry if there is a misunderstanding.