2.1.1) "Write a regular expression for the set of all alphabetic strings." Does this set include the empty string? It means the difference between using the Kleene star and the plus.
Whichever you want is fine, just be sure to note. I guess that I would consider the empty string to be an "all alphabetic string," but do whatever feels better to you :).
2.1.2) "... the set of all alphabetic strings ending in a 'b'." Similarly, does this set contain the string "b", which consists only of a single 'b'?
I would say that the string "b" is an alphabetic string that ends in a "b" :).
2.4) The book asks you to create a FSA, but it does not specify whether to use a DFSA or a NFSA. Are we allowed to use either? Also, the FSA supposed to validate dates, such as recognizing that "February 31" does not exist? Or is it simply supposed to recognize that it is a date string?
It's probably easier to produce a NFSA, so go ahead and do that if you want. (As you may or may not know yet, you can always convert one to the other.) Don't worry about handling bogus dates like Feb 31 or Sept 31, though you should not accept things like Feb 93 :).
You had mentioned in class today that you would post the problems from the book for those that haven't gotten the textbook yet. Will that be posted here or on the class webpage?
For the probability question, should we assume that 10% of the students who get A's give bad evals for random reasons (and then 95% of non-A students give bad evals because of their grade)?
Or that 10% of ALL students give bad evals for random reasons (and then, in addition, 95% of non-A students give bad evals because of their grade)?
Sorry, I'm not the one asked this question... I think he/she might buy an international version of this book and doesn't understand what the J+M stands for. Maybe he/she thinks its like sub-question 2.8.J, 2.8.M...
Here are a few questions that were emailed to me.
ReplyDelete2.1.1) "Write a regular expression for the set of all alphabetic strings." Does this set include the empty string? It means the difference between using the Kleene star and the plus.
Whichever you want is fine, just be sure to note. I guess that I would consider the empty string to be an "all alphabetic string," but do whatever feels better to you :).
2.1.2) "... the set of all alphabetic strings ending in a 'b'." Similarly, does this set contain the string "b", which consists only of a single 'b'?
I would say that the string "b" is an alphabetic string that ends in a "b" :).
2.4) The book asks you to create a FSA, but it does not specify whether to use a DFSA or a NFSA. Are we allowed to use either? Also, the FSA supposed to validate dates, such as recognizing that "February 31" does not exist? Or is it simply supposed to recognize that it is a date string?
It's probably easier to produce a NFSA, so go ahead and do that if you want. (As you may or may not know yet, you can always convert one to the other.) Don't worry about handling bogus dates like Feb 31 or Sept 31, though you should not accept things like Feb 93 :).
Hey Hal,
ReplyDeleteYou had mentioned in class today that you would post the problems from the book for those that haven't gotten the textbook yet. Will that be posted here or on the class webpage?
Thanks,
Michael
For the probability question, should we assume that 10% of the students who get A's give bad evals for random reasons (and then 95% of non-A students give bad evals because of their grade)?
ReplyDeleteOr that 10% of ALL students give bad evals for random reasons (and then, in addition, 95% of non-A students give bad evals because of their grade)?
I'm looking at 2.8 and don't see what you mean by J+M (I'm starting to think that my international version has something different?)
ReplyDeleteI did, and I never did it! I'm sorry. I actually didn't have access to my book since class. I'll be sure to do it in the future, though.
ReplyDelete(Sorry for the really tardy replies...)
ReplyDelete@Anonymous: it's the latter.. 10% of all students give bad evals.
@Souwa: I'm not sure what you mean :).
J+M: Jurafsky and Martin, authors of the textbook
ReplyDelete@Anonymous: No, I know J+M = Jurafsky & Martin.. I'm not sure about the rest of your question :).
ReplyDeleteSorry, I'm not the one asked this question...
ReplyDeleteI think he/she might buy an international version of this book and doesn't understand what the J+M stands for. Maybe he/she thinks its like sub-question 2.8.J, 2.8.M...
@Anonymous @hal yeah I thought you meant a subquestion J and M. Thanks!!
ReplyDeleteIn case you're having last minute issues including graphics, you probably want to try \usepackage{graphicx}.
ReplyDeleteIn case you're having last minute issues including graphics, you probably want to try \usepackage{graphicx}.
ReplyDelete