My Math Forum Quick question

 Real Analysis Real Analysis Math Forum

January 6th, 2017, 11:41 AM   #1
Senior Member

Joined: Oct 2016
From: Arizona

Posts: 209
Thanks: 37

Math Focus: I'm still deciding, but my recent focus has been olympiad problems and math journal problems.
Quick question

In reference to 2.34 Theorem is $V_q$ supposed to be $V_p$?
Attached Images
 IMG_5914.jpg (91.4 KB, 13 views)

January 6th, 2017, 12:05 PM   #2
Senior Member

Joined: Sep 2015
From: USA

Posts: 2,586
Thanks: 1430

This proof is almost identical but a bit clearer.

Attached Images
 Clipboard01.jpg (67.7 KB, 14 views)

January 6th, 2017, 12:22 PM   #3
Member

Joined: Dec 2016
From: USA

Posts: 46
Thanks: 11

Quote:
 Originally Posted by ProofOfALifetime In reference to 2.34 Theorem is $V_q$ supposed to be $V_p$?
No.

There is no such thing as $V_p$.

The sets $V_q,W_q$ are defined for points $q \in K$.

The proof in your book is valid.

Last edited by quasi; January 6th, 2017 at 12:30 PM.

 January 6th, 2017, 12:26 PM #4 Senior Member     Joined: Oct 2016 From: Arizona Posts: 209 Thanks: 37 Math Focus: I'm still deciding, but my recent focus has been olympiad problems and math journal problems. I've just never seen him refer to a neighborhood of $p$ using $V_q$ Thanks .
 January 6th, 2017, 12:28 PM #5 Senior Member     Joined: Oct 2016 From: Arizona Posts: 209 Thanks: 37 Math Focus: I'm still deciding, but my recent focus has been olympiad problems and math journal problems. I realize that there is no such thing as $V_p$ but thanks for pointing that out anyways. I was not questioning the validity of the proof, just the notation. Last edited by ProofOfALifetime; January 6th, 2017 at 12:30 PM.
January 6th, 2017, 12:37 PM   #6
Member

Joined: Dec 2016
From: USA

Posts: 46
Thanks: 11

Quote:
 Originally Posted by ProofOfALifetime I've just never seen him refer to a neighborhood of $p$ using $V_q$ Thanks .
But the author defines $V_q,W_q$ to be neigbhorhoods of $p,q$, respectively.

But they're not just any old neigborhoods. The radii are defined so as to force them to be disjoint.

For the proof in question, the point $p$ is fixed; the points $q$ vary (over the points of $K$).

The neighborhoods $V_q,W_q$ are defined based on the variable point $q \in K$.

Last edited by quasi; January 6th, 2017 at 12:49 PM.

 January 6th, 2017, 12:54 PM #7 Senior Member     Joined: Oct 2016 From: Arizona Posts: 209 Thanks: 37 Math Focus: I'm still deciding, but my recent focus has been olympiad problems and math journal problems. Okay I get it. Thanks quasi. I get the whole radii thing. I get the proof I guess the notation confused me a little at first.

 Tags question, quick

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post Timk Algebra 3 March 27th, 2012 10:31 PM hrdrok Algebra 3 March 18th, 2010 10:13 PM dabdias Calculus 3 April 8th, 2009 08:44 AM axelle Economics 1 May 17th, 2008 10:44 PM Kiranpreet Algebra 2 April 24th, 2008 02:02 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top