scholarly journals THE MAGIC NUMBER PROBLEM FOR SUBREGULAR LANGUAGE FAMILIES

2012 ◽  
Vol 23 (01) ◽  
pp. 115-131 ◽  
Author(s):  
MARKUS HOLZER ◽  
SEBASTIAN JAKOBI ◽  
MARTIN KUTRIB
Keyword(s):  
Finite Automaton ◽  
Magic Number ◽  
Regular Languages ◽  
Magic Numbers ◽  
Deterministic Finite Automaton ◽  
Number Problem ◽  
Nondeterministic Finite Automaton

We investigate the magic number problem, that is, the question whether there exists a minimal n-state nondeterministic finite automaton (NFA) whose equivalent minimal deterministic finite automaton (DFA) has α states, for all n and α satisfying n ≤ α ≤ 2n. A number α not satisfying this condition is called a magic number (for n). It was shown that no magic numbers exist for general regular languages, whereas trivial and non-trivial magic numbers for unary regular languages were identified. We obtain similar results for automata accepting subregular languages like, for example, star-free languages, prefix-, suffix-, and infix-closed languages, and prefix-, suffix-, and infix-free languages, showing that there are only trivial magic numbers, when they exist. For finite languages we obtain some partial results showing that certain numbers are non-magic.

MAGIC NUMBERS FOR SYMMETRIC DIFFERENCE NFAS

2005 ◽  
Vol 16 (05) ◽  
pp. 1027-1038 ◽  
Author(s):  
LYNETTE VAN ZIJL
Keyword(s):  
Finite Automaton ◽  
Finite Automata ◽  
Symmetric Difference ◽  
Magic Numbers ◽  
Deterministic Finite Automaton ◽  
Nondeterministic Finite Automata ◽  
Binary Case ◽  
Nondeterministic Finite Automaton

Iwama et al. showed that there exists an n-state binary nondeterministic finite automaton such that its equivalent minimal deterministic finite automaton has exactly 2n - α states, for all n ≥ 7 and 5 ≤ α ≤ 2n-2, subject to certain coprimality conditions. We investigate the same question for both unary and binary symmetric difference nondeterministic finite automata. In the binary case, we show that for any n ≥ 4, there is an n-state symmetric difference nondeterministic finite automaton for which the equivalent minimal deterministic finite automaton has 2n - 1 + 2k - 1 - 1 states, for 2 < k ≤ n - 1. In the unary case, we consider a large practical subclass of unary symmetric difference nondeterministic finite automata: for all n ≥ 2, we argue that there are many values of α such that there is no n-state unary symmetric difference nondeterministic finite automaton with an equivalent minimal deterministic finite automaton with 2n - α states, where 0 < α < 2n - 1. For each n ≥ 2, we quantify such values of α precisely.

DETERMINISTIC BLOW-UPS OF MINIMAL NONDETERMINISTIC FINITE AUTOMATA OVER A FIXED ALPHABET

2008 ◽  
Vol 19 (03) ◽  
pp. 617-631 ◽  
Author(s):  
JOZEF JIRÁSEK ◽  
GALINA JIRÁSKOVÁ ◽  
ALEXANDER SZABARI
Keyword(s):  
Finite Automaton ◽  
Finite Automata ◽  
Magic Numbers ◽  
Deterministic Finite Automaton ◽  
Nondeterministic Finite Automata ◽  
Letter Alphabet ◽  
Input Alphabet ◽  
Nondeterministic Finite Automaton

We show that for all integers n and α such that n ⩽ α ⩽ 2n, there exists a minimal nondeterministic finite automaton of n states with a four-letter input alphabet whose equivalent minimal deterministic finite automaton has exactly α states. It follows that in the case of a four-letter alphabet, there are no "magic numbers", i.e., the holes in the hierarchy. This improves a similar result obtained by Geffert for a growing alphabet of size n + 2.

MAGIC NUMBERS AND TERNARY ALPHABET

2011 ◽  
Vol 22 (02) ◽  
pp. 331-344 ◽  
Author(s):  
GALINA JIRÁSKOVÁ
Keyword(s):  
Finite Automaton ◽  
Magic Numbers ◽  
Deterministic Finite Automaton ◽  
Alphabet Size ◽  
Input Alphabet ◽  
Nondeterministic Finite Automaton

A number α, in the range from n to 2n, is magic for n with respect to a given alphabet size s, if there is no minimal nondeterministic finite automaton of n states and s input symbols whose equivalent minimal deterministic finite automaton has α states. We show that in the case of a ternary alphabet, there are no magic numbers. For all n and α satisfying n ⩽ α ⩽ 2n, we define an n-state nondeterministic finite automaton with a three-letter input alphabet that requires exactly α deterministic states.

scholarly journals Deterministic automata for extended regular expressions

2017 ◽  
Vol 7 (1) ◽  
pp. 24-28
Author(s):  
Mirzakhmet Syzdykov
Keyword(s):  
Finite Automaton ◽  
Regular Languages ◽  
Regular Expressions ◽  
Deterministic Finite Automaton ◽  
Past Work ◽  
The Past ◽  
Deterministic Automata ◽  
Extended Regular Expressions

Abstract In this work we present the algorithms to produce deterministic finite automaton (DFA) for extended operators in regular expressions like intersection, subtraction and complement. The method like “overriding” of the source NFA(NFA not defined) with subset construction rules is used. The past work described only the algorithm for AND-operator (or intersection of regular languages); in this paper the construction for the MINUS-operator (and complement) is shown.

scholarly journals ON A SUPERCLASS OF A-GRAMMARS

2017 ◽  
Vol 20 (10) ◽  
pp. 102-108
Author(s):  
V.P. Tsvetov
Keyword(s):  
Finite Automaton ◽  
Formal Languages ◽  
Regular Languages ◽  
Finite Alphabet ◽  
Graph Structure ◽  
Graph Grammars ◽  
Deterministic Finite Automaton

In this paper we consider a superclass of automaton grammars that can be represented in terms of paths on graphs. With this approach, we assume that vertices of graph are labeled by symbols of finite alphabet A . We will call such grammars graph-generated grammars or G-grammars. In contrast to the graph grammars that are used to describe graph structure transformations, G-grammars using a graphs as a means of representing formal languages. We will give an algorithm for constructing G-grammar which generate the language recognized by deterministic finite automaton. Moreover, we will show that the class of languages generated by G-grammars is a proper superset of regular languages.

scholarly journals Branching Measures and Nearly Acyclic NFAs

2019 ◽  
Vol 30 (06n07) ◽  
pp. 1135-1155
Author(s):  
Chris Keeler ◽  
Kai Salomaa
Keyword(s):  
Finite Automaton ◽  
Finite Depth ◽  
Regular Languages ◽  
Constant Density ◽  
Comprehensive Understanding ◽  
Letter Alphabet ◽  
Pass Through ◽  
Nondeterministic Finite Automaton

To get a more comprehensive understanding of the amount of branching in computations of a nondeterministic finite automaton (NFA), we introduce and study the string path width and depth path width measures. For a given NFA, the string path width on a string [Formula: see text] counts the number of all complete computations on [Formula: see text], and the depth path width on an integer [Formula: see text] counts the number of complete computations on all strings of length [Formula: see text]. We give an algorithm to decide the finiteness of the depth path width of an NFA. Deciding finiteness of string path width can be reduced to the corresponding question on ambiguity. An NFA is nearly acyclic if any computation can pass through at most one cycle. The class of nearly acyclic NFAs consists of exactly all NFAs with finite depth path width. Using this characterization we show that the finite depth path width of an [Formula: see text]-state NFA over a [Formula: see text]-letter alphabet is at most [Formula: see text] and that this bound is tight. The nearly acyclic NFAs recognize exactly the class of constant density regular languages.

scholarly journals IN SEARCH OF MOST COMPLEX REGULAR LANGUAGES

2013 ◽  
Vol 24 (06) ◽  
pp. 691-708 ◽  
Author(s):  
JANUSZ BRZOZOWSKI
Keyword(s):  
Positive Integer ◽  
Finite Automaton ◽  
Cyclic Permutation ◽  
The State ◽  
Regular Languages ◽  
Final States ◽  
Deterministic Finite Automaton ◽  
Small Positive Integer ◽  
Initial State ◽  
State Complexity

Sequences (Ln| n ≥ k), called streams, of regular languages Lnare considered, where k is some small positive integer, n is the state complexity of Ln, and the languages in a stream differ only in the parameter n, but otherwise, have the same properties. The following measures of complexity are proposed for any stream: (1) the state complexity n of Ln, that is, the number of left quotients of Ln(used as a reference); (2) the state complexities of the left quotients of Ln; (3) the number of atoms of Ln; (4) the state complexities of the atoms of Ln; (5) the size of the syntactic semigroup of Ln; and the state complexities of the following operations: (6) the reverse of Ln; (7) the star of Ln; (8) union, intersection, difference and symmetric difference of Lmand Ln; and (9) the concatenation of Lmand Ln. A stream that has the highest possible complexity with respect to these measures is then viewed as a most complex stream. The language stream (Un(a, b, c) | n ≥ 3) is defined by the deterministic finite automaton with state set {0, 1, … , n−1}, initial state 0, set {n−1} of final states, and input alphabet {a, b, c}, where a performs a cyclic permutation of the n states, b transposes states 0 and 1, and c maps state n − 1 to state 0. This stream achieves the highest possible complexities with the exception of boolean operations where m = n. In the latter case, one can use Un(a, b, c) and Un(b, a, c), where the roles of a and b are interchanged in the second language. In this sense, Un(a, b, c) is a universal witness. This witness and its extensions also apply to a large number of combined regular operations.

scholarly journals Finite Automata Implementations Considering CPU Cache

10.14311/1008 ◽  
2007 ◽  
Vol 47 (6) ◽  
Author(s):  
J. Holub
Keyword(s):  
Mathematical Models ◽  
Finite Automaton ◽  
Finite Automata ◽  
The Other ◽  
Practical Implementation ◽  
Deterministic Finite Automaton ◽  
Input Text ◽  
Finite State ◽  
Nondeterministic Finite Automaton

The finite automata are mathematical models for finite state systems. More general finite automaton is the nondeterministic finite automaton (NFA) that cannot be directly used. It is usually transformed to the deterministic finite automaton (DFA) that then runs in time O(n), where n is the size of the input text. We present two main approaches to practical implementation of DFA considering CPU cache. The first approach (represented by Table Driven and Hard Coded implementations) is suitable forautomata being run very frequently, typically having cycles. The other approach is suitable for a collection of automata from which various automata are retrieved and then run. This second kind of automata are expected to be cycle-free. 

scholarly journals AUTOMATA SEBAGAI MODEL PENGENAL BAHASA

2009 ◽  
Vol 1 (2) ◽  
pp. 53
Author(s):  
Eddy Maryanto
Keyword(s):  
Computer Program ◽  
Finite Automaton ◽  
Source Code ◽  
Computer Software ◽  
Deterministic Finite Automaton ◽  
Machine Code ◽  
Software Technology ◽  
Nondeterministic Finite Automaton

A deterministic finite automaton as well a nondeterministic finite automaton can be used to model a language recognizer. In computer software technology, language recognizer usually be an integrated part of a compiler, that is a computer program that take responsibility to translate source code into machine code. Comparing with a deterministic finite automaton, a nondeterministic finite automaton is a better model for language recognizer because it might be simpler and less in size than a deterministic one.

scholarly journals Accepting networks of evolutionary processors with resources restricted and structure limited filters

2021 ◽  
Vol 55 ◽  
pp. 8
Author(s):  
Jürgen Dassow ◽  
Bianca Truthe
Keyword(s):  
Finite Automaton ◽  
Regular Languages ◽  
Deterministic Finite Automaton ◽  
Production Rules ◽  
The Family

In this paper, we continue the research on accepting networks of evolutionary processors where the filters belong to several special families of regular languages. We consider families of codes or ideals and subregular families which are defined by restricting the resources needed for generating or accepting them (the number of states of the minimal deterministic finite automaton accepting a language of the family as well as the number of non-terminal symbols or the number of production rules of a right-linear grammar generating such a language). We insert the newly defined language families into the hierachy of language families obtained by using as filters languages of other subregular families (such as ordered, non-counting, power-separating, circular, suffix-closed regular, union-free, definite, combinational, finite, monoidal, nilpotent, or commutative languages).

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