Myhill graphs, Theory of Computation

Assignment Help:

Another way of representing a strictly 2-local automaton is with a Myhill graph. These are directed graphs in which the vertices are labeled with symbols from the input alphabet of the automaton (plus {x,x}), with an edge from a vertex labeled σ1 to a vertex labeled σ2 ix the pair σ1σ2 is included in T. (Note that if we interpret the strings in T as pairs of symbols, then the Myhill graph of A = (Σ, T) is just G = (Σ+, T).) The Myhill graph of the automaton of Figure 2 is given in Figure. For consistency with the graphs we will use later, the entry point to the graph is indicated with an edge "from nowhere" and the exit point is indicated by circling it.

The key property of Myhill graphs is that every path through the graph from the ‘x' node to the ‘x' node corresponds to a computation of the automaton and every computation of the automaton corresponds to such a path. So we can reason about the strings that are accepted by the automaton by reasoning about the sequences of nodes that occur on paths from ‘x' to ‘x'. (For simplicity, we will refer to paths from ‘x' to ‘x' as "paths through the graph".)

For example, the shortest strings in the language recognized by the automaton will those labeling the shortest paths through the graph, which is to say, the acyclic paths from ‘x' to ‘x'. In this particular case, these are the paths (x,x) and (x, a, b,x), corresponding to the strings ε and ab.


Related Discussions:- Myhill graphs

Java programming, 1. An integer is said to be a “continuous factored” if it...

1. An integer is said to be a “continuous factored” if it can be expresses as a product of two or more continuous integers greater than 1. Example of continuous factored integers

Operator p, implementation of operator precedence grammer

implementation of operator precedence grammer

Deterministic finite automata, conversion from nfa to dfa 0 | 1 ____...

conversion from nfa to dfa 0 | 1 ___________________ p |{q,s}|{q} *q|{r} |{q,r} r |(s) |{p} *s|null |{p}

Complement - operations on languages, The fact that SL 2 is closed under i...

The fact that SL 2 is closed under intersection but not under union implies that it is not closed under complement since, by DeMorgan's Theorem L 1 ∩ L 2 = We know that

Myhill-nerode theorem, This close relationship between the SL2 languages an...

This close relationship between the SL2 languages and the recognizable languages lets us use some of what we know about SL 2 to discover properties of the recognizable languages.

Give the acyclic paths through your graph, Give the Myhill graph of your au...

Give the Myhill graph of your automaton. (You may use a single node to represent the entire set of symbols of the English alphabet, another to represent the entire set of decima

Design and implementation of the state machine, You are required to design ...

You are required to design a system that controls the speed of a fan's rotation. The speed at which the fan rotates is determined by the ambient temperature, i.e. as the temperatur

Language accepted by a nfa, The language accepted by a NFA A = (Q,Σ, δ, q 0...

The language accepted by a NFA A = (Q,Σ, δ, q 0 , F) is NFAs correspond to a kind of parallelism in the automata. We can think of the same basic model of automaton: an inpu

Computations of sl automata, We will specify a computation of one of these ...

We will specify a computation of one of these automata by specifying the pair of the symbols that are in the window and the remainder of the string to the right of the window at ea

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd