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Just a layman and slow learner. Thank you for your enlightenment and patience, and for giving me the best memory in my life.


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
May
28
accepted Completion of algebraic numbers?
May
28
comment Completion of algebraic numbers?
@Robert: I don't know. I wonder if there is some order on the set of algebraic numbers so that the set can be completed with respect to?
May
28
comment Completion of algebraic numbers?
Thanks! Does the set of algebraic numbers have an order to complete with respect to?
May
27
asked Completion of algebraic numbers?
May
27
comment Function $F$ that $F(x)+F(-x)=\lim_{y\rightarrow\infty}F(y), \forall x \in \mathbb{R}$
@Didier: Thanks! The notation was copied from Chung's book and at first confused me.
May
27
accepted least-upper-bound and greatest-lower-bound properties