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  2. Dyck language - Wikipedia

    en.wikipedia.org/wiki/Dyck_language

    In the theory of formal languages of computer science, mathematics, and linguistics, a Dyck word is a balanced string of brackets. The set of Dyck words forms a Dyck language. The simplest, Dyck-1, uses just two matching brackets, e.g. ( and ). Dyck words and language are named after the mathematician Walther von Dyck.

  3. Lobb number - Wikipedia

    en.wikipedia.org/wiki/Lobb_number

    In combinatorial mathematics, the Lobb number L m,n counts the ways that n + m open parentheses and n − m close parentheses can be arranged to form the start of a valid sequence of balanced parentheses. [1] Lobb numbers form a natural generalization of the Catalan numbers, which count the complete strings of balanced parentheses of a given ...

  4. Pumping lemma for regular languages - Wikipedia

    en.wikipedia.org/wiki/Pumping_lemma_for_regular...

    The proof that the language of balanced (i.e., properly nested) parentheses is not regular follows the same idea. Given p {\displaystyle p} , there is a string of balanced parentheses that begins with more than p {\displaystyle p} left parentheses, so that y {\displaystyle y} will consist entirely of left parentheses.

  5. Perl Compatible Regular Expressions - Wikipedia

    en.wikipedia.org/wiki/Perl_Compatible_Regular...

    A sub-pattern (surrounded by parentheses, ... will match any combination of balanced parentheses and "a"s. Generic callouts. PCRE expressions can embed ...

  6. Syntactic monoid - Wikipedia

    en.wikipedia.org/wiki/Syntactic_monoid

    The bicyclic monoid is the syntactic monoid of the Dyck language (the language of balanced sets of parentheses). The free monoid on A {\displaystyle A} (where | A | > 1 {\displaystyle \left|A\right|>1} ) is the syntactic monoid of the language { w w R ∣ w ∈ A ∗ } {\displaystyle \{ww^{R}\mid w\in A^{*}\}} , where w R {\displaystyle w^{R ...

  7. Bracket - Wikipedia

    en.wikipedia.org/wiki/Bracket

    and ) are parentheses / p ə ˈ r ɛ n θ ɪ s iː z / (singular parenthesis / p ə ˈ r ɛ n θ ɪ s ɪ s /) in American English, and either round brackets or simply brackets in British English. [1] [4] They are also known as "parens" / p ə ˈ r ɛ n z /, "circle brackets", or "smooth brackets". In formal writing, "parentheses" is also used ...

  8. More than 800 people have lost their lives in jail since July 13, 2015 but few details are publicly released. Huffington Post is compiling a database of every person who died until July 13, 2016 to shed light on how they passed.

  9. Context-free grammar - Wikipedia

    en.wikipedia.org/wiki/Context-free_grammar

    In contrast to well-formed nested parentheses and square brackets in the previous section, there is no context-free grammar for generating all sequences of two different types of parentheses, each separately balanced disregarding the other, where the two types need not nest inside one another, for example: [ ( ] ) or