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Jul
17
accepted Can a formal language always be generated by a formal grammar?
Jul
14
accepted Understanding recursion in λ calculus
Jul
14
revised Understanding recursion in λ calculus
edited tags
Jul
14
asked Understanding recursion in λ calculus
Jul
12
comment The way that a regular expression describes a regular language
@Gerry: My questions are two: (1) Is regular expression some kind of formal grammar? Or at least very close related in the sense that one can be derived trivially from the other? (2) For other non-regular languages which can have formal grammars, is it possible that they can be described by some generalized versions of regular expression? Note that I know they cannot be described by regular expression, or else they would have been regular languages.
Jul
12
accepted Existence of the $P$ closure of binary relation $R$
Jul
11
asked Existence of the $P$ closure of binary relation $R$
Jul
11
comment The way that a regular expression describes a regular language
@joriki: Thanks for pointing it out. I intended to mean "For a regular <del> expression </del> language, it can also be described by a regular expression."
Jul
11
revised The way that a regular expression describes a regular language
deleted 2 characters in body
Jul
11
comment Can a formal language always be generated by a formal grammar?
Is the relation between a formal language and a formal grammar similar to the relation between a formal language and an automaton, as asked in my Part 2?
Jul
11
comment Can a formal language always be generated by a formal grammar?
(1) what's the definition used in your post then? (2) Is this similar to the relation between a formal language and an automaton, asked in my Part 2?
Jul
11
revised Can a formal language always be generated by a formal grammar?
added 153 characters in body
Jul
11
comment Can a formal language always be generated by a formal grammar?
Thanks! The definition I know is en.wikipedia.org/wiki/Formal_grammar#Formal_definition . What are the different definitions?
Jul
11
comment Can a formal language always be generated by a formal grammar?
Thanks! The definition I know is en.wikipedia.org/wiki/Formal_grammar#Formal_definition . Are there different definitions?
Jul
11
asked The way that a regular expression describes a regular language
Jul
11
revised Can a formal language always be generated by a formal grammar?
added 61 characters in body
Jul
11
asked Can a formal language always be generated by a formal grammar?
Jul
11
accepted Is the encoding process in coding theory a hash function?
Jul
11
accepted Is a regular expression a string or a set of strings?
Jul
11
comment Is a regular expression a string or a set of strings?
@Theo: Thanks! Some use hollow while some use solid, and I changed to solid one. I also corrected the name of the author: spiser -> sipser. Yes, it has been a while with my focus on other silly things.