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Theory of Semi-Feasible Algorithms
Lane A. Hemaspaandra
Leen Torenvliet
出版
Springer Science & Business Media
, 2013-04-17
主題
Computers / Programming / General
Computers / Programming / Algorithms
Computers / Machine Theory
Computers / Data Science / General
Mathematics / Combinatorics
Computers / Information Technology
Computers / Computer Science
Mathematics / Discrete Mathematics
Mathematics / Numerical Analysis
ISBN
3662050803
9783662050804
URL
http://books.google.com.hk/books?id=rMeqCAAAQBAJ&hl=&source=gbs_api
EBook
SAMPLE
註釋
An Invitation to the Dance It is an underappreciated fact that sets may have various types of complex ity, and not all types are in harmony with each other. The primary goal of this book is to unify and make more widely accessible a vibrant stream of research-the theory of semi-feasible computation-that perfectly showcases the richness of, and contrasts between, the central types of complexity. The semi-feasible sets, which are most commonly referred to as the P selective sets, are those sets L for which there is a deterministic polynornial time algorithm that, when given as input any two strings of which at least one belongs to L, will output one of them that is in L. The reason we saythat the semi-feasible sets showcase the contrasts among types of complexity is that it is well-known that many semi-feasible sets have no recursive algorithms (thus their time complexitycannot be upper-bounded by standard time-complexity classes), yet all semi-feasible sets are simple in a wide range of other natural senses. In particular, the semi-feasible sets have small circuits, they are in the extended low hierarchy, and they cannot be NP-complete unless P = NP. The semi-feasible sets are fascinating for many reasons. First, as men tioned above, they showcase the fact that mere deterministic time complex ity is not the only potential type of complexity in the world of computation.