Regular Expressions 2018 Dr Sandip Mal 1 Regular
- Slides: 35
Regular Expressions 2018 Dr. Sandip Mal 1
Regular Expressions Regular expressions describe regular languages Example: describes the language 2018 Dr. Sandip Mal 2
Recursive Definition Primitive regular expressions: Given regular expressions and Are regular expressions 2018 Dr. Sandip Mal 3
Examples A regular expression: Not a regular expression: 2018 Dr. Sandip Mal 4
Languages of Regular Expressions : language of regular expression Example 2018 Dr. Sandip Mal 5
Definition For primitive regular expressions: 2018 Dr. Sandip Mal 6
Definition (continued) For regular expressions 2018 Dr. Sandip Mal and 7
Example Regular expression: 2018 Dr. Sandip Mal 8
Example Regular expression 2018 Dr. Sandip Mal 9
Example Regular expression 2018 Dr. Sandip Mal 10
Example Regular expression = { all strings containing substring 00 } 2018 Dr. Sandip Mal 11
Example Regular expression = { all strings without substring 00 } 2018 Dr. Sandip Mal 12
Equivalent Regular Expressions Definition: Regular expressions and are equivalent if 2018 Dr. Sandip Mal 13
Example = { all strings without substring 00 } and are equivalent regular expressions 2018 Dr. Sandip Mal 14
Regular Expressions and Regular Languages 2018 Dr. Sandip Mal 15
Theorem Languages Generated by Regular Expressions 2018 Dr. Sandip Mal Regular Languages 16
Proof: Languages Generated by Regular Expressions Regular Languages 2018 Dr. Sandip Mal 17
Proof - Part 1 Languages Generated by Regular Expressions Regular Languages For any regular expression the language is regular Proof by induction on the size of 2018 Dr. Sandip Mal 18
Induction Basis Primitive Regular Expressions: Corresponding NFAs regular languages 2018 Dr. Sandip Mal 19
Inductive Hypothesis Suppose that for regular expressions and , and are regular languages 2018 Dr. Sandip Mal 20
Inductive Step We will prove: Are regular Languages 2018 Dr. Sandip Mal 21
By definition of regular expressions: 2018 Dr. Sandip Mal 22
By inductive hypothesis we know: and are regular languages We also know: Regular languages are closed under: Union Concatenation Star 2018 Dr. Sandip Mal 23
Therefore: Are regular languages is trivially a regular language (by induction hypothesis) 2018 Dr. Sandip Mal End of Proof-Part 1 24
Using the regular closure of these operations, we can construct recursively the NFA that accepts Example: 2018 Dr. Sandip Mal 25
Proof - Part 2 Languages Generated by Regular Expressions Regular Languages For any regular language there is a regular expression with We will convert an NFA that accepts to a regular expression 2018 Dr. Sandip Mal 26
Since NFA is regular, there is a that accepts it Take it with a single final state 2018 Dr. Sandip Mal 27
From construct the equivalent Generalized Transition Graph in which transition labels are regular expressions Example: 2018 Corresponding Generalized transition graph Dr. Sandip Mal 28
Another Example: Transition labels are regular expressions 2018 Dr. Sandip Mal 29
Reducing the states: Transition labels are regular expressions 2018 Dr. Sandip Mal 30
Resulting Regular Expression: 2018 Dr. Sandip Mal 31
In General Removing a state: 2018 Dr. Sandip Mal 32
By repeating the process until two states are left, the resulting graph is Initial graph Resulting graph The resulting regular expression: 2018 Dr. Sandip Mal End of Proof-Part 2 33
Standard Representations of Regular Languages DFAs NFAs 2018 Dr. Sandip Mal Regular Expressions 34
When we say: We mean: We are given a Regular Language is in a standard representation (DFA, NFA, or Regular Expression) 2018 Dr. Sandip Mal 35
- Mal. 3:10
- Sapiencial sinonimo
- Bien mal regular
- Bien mal regular
- B a f c j e
- Perl5 正規表現
- Regular expressions
- Inductive definition of regular expressions
- Primitive regular expressions
- Xkcd regexp
- Regular expressions wikipedia
- Regular expressions
- How do you simplify a rational expression
- Regular expressions
- Every linear grammar generates a regular language
- Dibbys girilmiyor
- Cv-mal
- Deus não criou o mal catequese
- Parroquia nuestra señora de la salud
- Mal de vivre romantisme
- Dico che quando l'anima mal nata
- Mal brossard catcher in the rye
- Risikoanalyse mal word
- Innkomstjournal mal
- Vicio barbarismo
- Jesus é valente na batalha
- Mal-entendido
- Uit powerpoint mal
- Dış büyüme yöntemleri
- Mal rossino uomo
- Smarta mål mall
- Mal utviklingssamtale
- Porque el pecado es un mal
- Chanter paroles de claude lemesle
- Pal mal cleanroom
- Pal mal cleanroom