A string is a finite set sequence of symbols choosen from some alphabets.For example, 00011001 is a string from binary alphabet Σ={0, 1}aabbcabcd is a string from alphabet Σ={a, b, c, d}The different operations performed on strings are explained below −Concatenation.Substring.Kleen star operation.Reversal.ConcatenationConcatenation is nothing but combining the two strings ... Read More

A finite state machine has a set of states and two functions called the next-state and output function.The set of states correspond to all the possible combinations of the internal storage. If there are n bits of storage, there are 2n possible states.The next state function is a combinational logic ... Read More

There are two methods for converting a Deterministic Finite Automata (DFA) to Regular expression (RE). These methods are as follows −Arden's Theorem Method.State Elimination Method.Let us understand the Arden's Theorem method in detail.Arden's TheoremLet P and Q be the two regular expressions.If P does not contain null string, then the ... Read More

If Σ is an alphabet, the set of all strings can be expressed as a certain length from that alphabet by using exponential notation. The power of an alphabet is denoted by Σk and is the set of strings of length k.For example, Σ ={0, 1}Σ1= {0, 1} ( 21=2)Σ2= ... Read More

The basic definitions of the fundamental concepts in the Theory of Computation (TOC) along with the relevant examples are explained below −SymbolSymbols simply call it as a character.It is an atomic unit, such as a digit, character, lowercase letter, etc. Sometimes it is also a word. The formal language does ... Read More

Derivation is a sequence of production rules. It is used to get input strings. During parsing, we have to take two decisions, which are as followsWe have to decide the non-terminal which is to be replaced.We have to decide the production rule by which the non-terminal will be replaced.Two options ... Read More

ProblemDerive the string"00101" for left most derivation (LMD) and right most derivation (RMD) using context free grammar (CFG).SolutionThe grammar is as follows −S->A1B A->0A| ε B->0B| 1B| εLeft Most derivation (LMD)In the left most derivation, the given input is scanned and then replaced with the production rule from left side ... Read More

Closure property is a technique to understand the class of the resulting language when we are performing an operation on two languages of the same class.That means, suppose L1 and L2 belong to regular language and if regular language is closed under operation ∪, then L1∪L2 will be a Regular ... Read More

ProblemGenerate RE for a given finite automata by using the state elimination method.SolutionThere are two methods for converting a Deterministic Finite Automata (DFA) to Regular expression (RE).Arden's Theorem Method.State Elimination Method.The given automata is as follows−Step 1Initial state is A that has an incoming edge.So, we have to create a ... Read More

ProblemGiven a Finite Automata, we need to convert the Finite Automata into equivalent Regular Expression using the State Elimination Method.Step 1 − Initial state q1 has incoming edge. So, create a new initial state qi.Step 2 − Final state q2 has outgoing edge. So, create a new final state.Step 3 ... Read More