Grammars and languages: Chomsky’s hierarchy
N. Chomsky: Three models are there for the explanation of language.
Motivating illustration:
Sentence -> Noun Verb Noun, example: Bob loves Alice.
Sentence -> Sentence Conjunction Sentence, example: Bob loves Alice and Rome fights Carthage.
Grammar G(V, A, P, S). V: alphabet of the non-terminal symbols, variables and grammatical types;
A: alphabet of the terminal symbols, S ∈ V: start symbol, ‘sentence’;
P: unordered set of the productions of form L -> R, where L, R ∈ (V ∪ A)*
Rewriting step: for x, y, y’, z ∈ (V ∪ A)*, u -> v if u = xyz, v = xy’z and y -> y’ ∈ P
Derivation: “->*” is the transitive, reflexive closure of “->”, that is, u ->* v iff ∃ w0, w1 ... wj, with j ≥ 0, u = w0, w(i-1) -> wi, wj = v
Language defined by G: L(G) = {w ∈ A* | S ->* w)
Different restrictions on the productions define various types of grammars and corresponding languages:
Type 0: Phrase structure grammar: No restrictions
Type 1: Context sensitive: |L| ≤ |R|, (exception: S -> ε is permitted when S never takes place on any right-hand side)
Type 2: context free: L ∈ V
Type 3: regular: L ∈ V, R = a or R = aX, where a ∈ A, X ∈ V
Exercise: Define a grammar for some very small subset of natural language, and exemplify it with illustrations. Try this for a subset of English and a semantically identical subset of the other language, and show that distinct natural languages encompass different grammars.
Latest technology based Theory of Computation Online Tutoring Assistance
Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Theory of Computation help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Theory of Computation, project ideas and tutorials. We provide email based Theory of Computation help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Theory of Computation. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Theory of Computation Homework help and assignment help services. They use their experience, as they have solved thousands of the Theory of Computation assignments, which may help you to solve your complex issues of Theory of Computation. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.
www.tutorsglobe.com offers acidity of terminal alkynes homework help, assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
Theory and lecture notes of Graphs and Equations all along with the key concepts of graphs and equations, homework help, assignment help and understanding macroeconomics. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Graphs and Equations.
tutorsglobe.com collection of rainwater from terrace assignment help-homework help by online rain water harvesting tutors
tutorsglobe.com searching algorithm assignment help-homework help by online computer science tutors
tutorsglobe.com angina pectoris assignment help-homework help by online circulation tutors
Theory and lecture notes of Price level and Inflation all along with the key concepts of Price level and inflation, Consumer Price Index, Inflation Rate, Paasche index and Laspeyres index. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Price level and inflation.
Fresnel Diffraction tutorial all along with the key concepts of Observing Diffraction, Producing a Diffraction Pattern and Fresnel Construction
www.tutorsglobe.com offers multivariable calculus homework help, multivariable calculus assignment help, online tutoring assistance, maths solutions by online qualified tutor’s help.
Industrial Chemical Processes tutorial all along with the key concepts of Basic chemicals, Speciality chemicals, Consumer chemicals, Where are chemical sites located, Chemical industry: how safe and how environmentally regulated and challenges for chemical industry
Financial Accounting aims at carrying out the results of an accounting year in terms of profits or losses and assets and liabilities.
www.tutorsglobe.com offers Layering homework help, assignment help, case study, writing homework help, online tutoring assistance by computer science tutors.
Theory and lecture notes of Cournot Duopoly all along with the key concepts of cournot duopoly, cournot duopoly Assumptions, Cournot-Nash Equilibrium, Generalization to Oligopoly. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Cournot Duopoly.
tutorsglobe.com economic importance of gymnosperms assignment help-homework help by online spermatophytes tutors
www.tutorsglobe.com offers properties of aldehydes and ketones homework help, properties of aldehydes and ketones assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
tutorsglobe.com medieval philosophy assignment help-homework help by online humanities tutors
1952317
Questions Asked
3689
Tutors
1461856
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!