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 hydration & tautomerism homework help, hydration & tautomerism assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
Get your complicated assignments resolved by qualified Feminist Philosophy Assignment Help tutors at rational prices.
tutorsglobe.com applications of plant tissue culture assignment help-homework help by online plant tissue culture tutors
Introduction to Organic Chemistry III tutorial all along with the key concepts of Properties of Organic Compounds, History of Organic Chemistry, Difference between Organic and an Inorganic Compound, Classification of Organic Compounds, IUPAC Nomenclature of Organic Compounds
Superposition of Harmonic Oscillations tutorial all along with the key concepts of Superposition of two harmonic oscillations of same frequency along same line, Uniform Circular Motion and SHM, Vector Addition, Oscillations in two dimensions
theory and lecture notes of static characteristics ii, all along with the key concepts of simple transistor inverter, base overdrive factor, base charge in saturation and physical mechanism in saturation. tutorsglobe offers homework help, assignment help and tutor’s assistance on static characteristics ii.
The function of interim financial statements has significant implications for the measurement of interim profit.
Top-rated Included Applications Assignment Help service is offered by professional tutors, with 24x7 support at affordable prices to score high.
tutorsglobe.com imperfections in solids assignment help-homework help by online solid state chemistry tutors
We bring to you industry best Global Change-Issues and Impacts Assignment Help tutors round the clock to help you to score A++ grades!
financial gearing takes place while a business is financed, at least in part, through borrowing instead of through finance given through the owners (the shareholders) as equity.
tutorsglobe.com intermolecular forces assignment help-homework help by online atomic structure tutors
tutorsglobe.com root-stem and leaf assignment help-homework help by online plant morphology tutors
tutorsglobe.com transfer of genes to fertilized eggs assignment help-homework help by online transgenic organisms tutors
Stellar Atmospheres tutorial all along with the key concepts of Classification of Stellar Atmosphere, Model of Stellar Atmosphere, Standard Solar Model, Solar Radiation, Relationship with Sun, Black Body Radiation
1932496
Questions Asked
3689
Tutors
1448103
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!