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June 30th, 2017, 07:23 AM  #1 
Member Joined: Jan 2016 From: United Kingdom Posts: 32 Thanks: 0  result about arithmetic of convergent sequences
Hello all, I believe that, given a collection of increasing sequences whose total sum converges, each individual sequence will also converge. Attached is my short proof. Is it correct? Regards, Magnitude 
June 30th, 2017, 07:49 AM  #2 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,030 Thanks: 2341 Math Focus: Mainly analysis and algebra 
Your first line seems to state that all the sequences diverge. Comments:
Last edited by v8archie; June 30th, 2017 at 08:07 AM. 
June 30th, 2017, 08:31 AM  #3 
Member Joined: Jan 2016 From: United Kingdom Posts: 32 Thanks: 0 
V8archie, In my first line, I failed to mention the "collection" is a subset of the original bunch. Then I suppose such a collection could diverge, but then their sum diverges and adding all the rest in (which, having not been included in the collection are bounded above) gives that the total diverges, which is a contradiction. Is this sufficient? Meanwhile, I'm trying the induction approach now. Last edited by skipjack; June 30th, 2017 at 01:48 PM. 

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arithmetic, convergent, result, sequences 
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