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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.
Jul
11
revised Is a regular expression a string or a set of strings?
edited body
Jul
11
comment Is a regular expression a string or a set of strings?
Thanks! In 5, it is supposed to be a central hollow dot meaning concatenation.
Jul
11
asked Is a regular expression a string or a set of strings?
Jul
11
comment Is the encoding process in coding theory a hash function?
Thanks! I still don't understand well. As far as I know, both encoding and hash function try to map different pieces of information to different integers, with possibly other objectives.
Jul
11
asked Is the encoding process in coding theory a hash function?
Jun
13
awarded  Fanatic
Jun
6
awarded  Taxonomist
Jun
6
accepted Meaning of justify
May
30
comment Meaning of justify
@Qiaochu: Thanks! Do you mean necessary condition of the conclusion by "evidence"?
May
30
asked Meaning of justify