Timeline for Given a string and a CFG, what characters can follow the string (in the sentential forms of the CFG)?
Current License: CC BY-SA 3.0
22 events
| when toggle format | what | by | license | comment | |
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| Mar 27, 2012 at 3:05 | comment | added | Kaveh | It might be helpful in reading the question if you state more explicitly what is the output and what you mean by determining a set. | |
| Mar 27, 2012 at 3:04 | history | edited | Kaveh |
edited tags
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| Mar 21, 2012 at 17:01 | history | edited | Raphael | CC BY-SA 3.0 |
added 30 characters in body
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| Mar 21, 2012 at 16:40 | vote | accept | Thomas | ||
| Mar 21, 2012 at 15:43 | comment | added | Thomas | Thank you for your comments! I have edited it again in an attempt to make it more clear | |
| Mar 21, 2012 at 15:41 | history | edited | Thomas | CC BY-SA 3.0 |
clarification and more precise description of the problem
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| Mar 21, 2012 at 14:13 | comment | added | Janoma | @Raphael Thanks. So it is just a name for intermediate words that can be derived starting from $S$. In that case, I agree with you that Thomas should edit the question to clarify the notation. | |
| Mar 21, 2012 at 12:34 | comment | added | Raphael | @Thomas "In this case, $x,a,y,b$ are non-terminals." -- that does not make sense in the context of $xay \in \mathcal{L}(G)$. Please edit to clarify; maybe it is best to give terminal and non-terminal alphabet explicit names. | |
| Mar 21, 2012 at 12:33 | comment | added | Raphael | @Janoma: See here. | |
| S Mar 21, 2012 at 12:16 | history | suggested | uli | CC BY-SA 3.0 |
avoid opening and closing lines
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| Mar 21, 2012 at 7:09 | review | Suggested edits | |||
| S Mar 21, 2012 at 12:16 | |||||
| Mar 21, 2012 at 1:52 | comment | added | Janoma | What are the sentential forms of $G$? | |
| Mar 21, 2012 at 1:02 | comment | added | Alex ten Brink | Firstly, if the $x$ and $y$ in your first sentence are different from the $x$ and $y$ in the set definition, it might not be a bad idea to name them differently, to avoid confusion. Secondly, are you sure that you don't mean that $x$, $y$ and $a$ are strings of non-terminals? Thirdly, you say $a$ is a non-terminal, but later you consider the case that $a$ is a character, but characters=terminals; are you sure it's what you mean this way? I have an answer almost ready, just checking if I get your question :) | |
| Mar 21, 2012 at 0:30 | comment | added | Thomas | I hope that I didn't change the question too much - it has a slightly different nature now. | |
| Mar 21, 2012 at 0:29 | history | edited | Thomas | CC BY-SA 3.0 |
Trying to make the question more precise; However this changes the question a bit.
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| Mar 21, 2012 at 0:22 | comment | added | Thomas | @Raphael - I'm trying to automate transformations of L-System grammars... so it's not in normal form. In fact I will edit this question again to make it more precise. | |
| Mar 21, 2012 at 0:17 | comment | added | Thomas | @AlextenBrink - $x$ and $y$ are arbitrary strings. I'm just looking at a fragment/substring. | |
| Mar 20, 2012 at 23:16 | answer | added | Alex ten Brink | timeline score: 6 | |
| Mar 20, 2012 at 23:07 | comment | added | Raphael | Can we assume the grammar is in any normal form or does it have to work for arbitrary ones? | |
| Mar 20, 2012 at 23:03 | history | edited | Raphael | CC BY-SA 3.0 |
clearing up notation
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| Mar 20, 2012 at 23:01 | comment | added | Raphael | What is your application? Are you building a parser? | |
| Mar 20, 2012 at 22:55 | history | asked | Thomas | CC BY-SA 3.0 |