Question about this set-theory identity

  • #1
MathematicalPhysicist
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I am reading this book:
https://web.stanford.edu/class/math285/ts-gmt.pdf
on page 2 in remark 1.5(1), it's written that:
##\cap_{j=1}^\infty A_j = X\setminus (X\setminus \cup_{j=1}^\infty A_j)##
this seems totally wrong, shouldn't it be ##X\setminus \cup_{j=1}^\infty (X\setminus A_j)## ?

I wonder if this book has other such pitfalls...
 

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  • #2
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I agree with you.
 
  • #3
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cap and cup is a typo that can easily be made, e.g. by cut and paste. I think you cannot derive the value of an entire script from a simple typo.
 
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  • #4
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Proofreading a text is a tedious, thankless job that is never finished. No matter how hard one tries, there are still mistakes. If you want to minimize the chance of occasional errors, look for books that have been around for decades and have had many prior editions.
 
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  • #5
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Proofreading a text is a tedious, thankless job that is never finished. No matter how hard one tries, there are still mistakes. If you want to minimize the chance of occasional errors, look for books that have been around for decades and have had many prior editions.
This book was recommended for a Geometric Measure Theory course I am watching in zoom.
I am not taking the course for credit or anything like that.
A few years ago I started reading Herbert Federer's book, perhaps I should return to it.
 
  • #6
S.G. Janssens
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If this is your first course on the subject, I would stick with this introduction and see if you like to participate in the Zoom sessions. Federer is not an introduction but a treatise.

And I would just send a brief email to the author to let him know about what is probably a typo. (Or you can collect some more and send him a list.) Just be sure to have the current version of the book, as this is from 2014 and advertised as a draft. So the typo may already have been corrected.
 
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  • #7
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If this is your first course on the subject, I would stick with this introduction and see if you like to participate in the Zoom sessions. Federer is not an introduction but a treatise.

And I would just send a brief email to the author to let him know about what is probably a typo. (Or you can collect some more and send him a list.) Just be sure to have the current version of the book, as this is from 2014 and advertised as a draft. So the typo may already have been corrected.
Hi, do you know perhaps where can I find a copy of the book which did get published?
I cannot find it in Amazon.
 
  • #8
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cap and cup is a typo that can easily be made, e.g. by cut and paste. I think you cannot derive the value of an entire script from a simple typo.
I didn't derive, I wondered.
different words, big difference...
 
  • #9
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I think I'll retry Federer's book.
As the saying goes:"

Fortune Favours the Brave​

"
 

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