# Talk:Complexity theory

WikiProject Disambiguation
This page is within the scope of WikiProject Disambiguation, an attempt to structure and organize all disambiguation pages on Wikipedia. If you wish to help, you can edit the page attached to this talk page, or visit the project page, where you can join the project and/or contribute to the discussion.
WikiProject Computer science (Rated Disambig-class)
This page is within the scope of WikiProject Computer science, a collaborative effort to improve the coverage of Computer science related articles on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Disambig  This page does not require a rating on the project's quality scale.
WikiProject Systems (Rated Disambig-class, High-importance)
This page is within the scope of WikiProject Systems, which collaborates on articles related to systems and systems science.
Disambig  This page does not require a rating on the project's quality scale.
High  This page has been rated as High-importance on the project's importance scale.
This page is within the field of Systems theory.

## Also

The study of complex systems is also called complexity theory, which is apparently quite a different subject then the one being discussed here.

Perhaps this article should be Computational Complexity Theory.

I've added a link at the bottom of the article. Feel free to write that up. I'd be very interested in reading an overview of that kind of complexity theory. -LC

I always thought that NP-hard problems need not be decision problems. For instance, finding the shortest roundtrip in a weighted graph is NP-hard; deciding whether a roundtrip shorter than a given number exists is NP-complete. --AxelBoldt

Yes, that's right. The article doesn't say an NP-hard problem must be a "decision problem". It just says it must be a "problem". It's correct; it just didn't give much detail. That paragraph also didn't use the word "reducibility", or distinguish the two types of reductions. It also didn't describe when you'd be interested in polytime reductions (e.g. for NP-Hard), and when you'd be interested in something else (e.g. for P-Hard).
My intent was to put the details in the NP-Hard article which is linked to, but isn't written yet. Feel free to expand that paragraph, if you'd like. Or write the NP-Hard article. - LC

## Complexity

Where should the Complexity article fit on this disambiguation page? - Theboywonder 07:29, 19 October 2005 (UTC)

Duplicate. Sorry. (Theboywonder 14:20, 19 October 2005 (UTC))