Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | ACM Digital Library |
|---|---|
| Author | Hunt, H. B. Rosenkrantz, D. J. |
| Abstract | This paper presents a complexity theory of formal languages. The main technique used is that of embedding “&equil;{0,1}*”, “&equil;0*”, and “&equil;&fgr;” into other linguistic predicates. In Section 2, the undecidability of “&equil;{0,1}*” for cfl's is exploited to provide sufficient conditions for the undecidability of predicates on the cfl's. In Section 3, the same techniques are applied to regular sets. Predicates satisfying conditions similar to those of Section 2 are shown to be hard, where how hard depends on the descriptors used to enumerate the regular sets. Section 4 concentrates on the equivalence and containment problems for cfl's. For cfl's, regular sets, and linear cfl's, the complexity of determining equivalence to a fixed language is linked to whether the fixed language is finite, infinite but bounded, or unbounded. In Section 5, the ability of cfg's to generate finite languages whose strings are exponential in the size of the grammar is used to obtain exponential lower bounds on several decidable problems for cfg's generating finite sets. In Section 6, all nontrivial predicates for certain specific classes of languages are shown to be hard. In Section 7, we show that a dpda can always be converted in polynomial time into an equivalent dpda that always halts. Therefore the predicate “&equil;{0,1}*” is in P for dpda's, and embedding this problem into other predicates on the dpda's will not yield nonpolynomial lower bounds. In Section 8, some of the preceding results are generalized to other families of languages. |
| Starting Page | 64 |
| Ending Page | 74 |
| Page Count | 11 |
| File Format | |
| DOI | 10.1145/800119.803885 |
| Language | English |
| Publisher | Association for Computing Machinery (ACM) |
| Publisher Date | 1974-04-30 |
| Publisher Place | New York |
| Access Restriction | Subscribed |
| Content Type | Text |
| Resource Type | Article |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|