I love that you never pronounce “Cauchy” the same way twice lol
@punditgi4 жыл бұрын
Such an eye opening explanation!
@vadimpavlov6037 Жыл бұрын
I think the final step relies on the fact that R contains all its lim sups and lim infs, for otherwise the same argument would apply to Q
@hauntedmasc4 жыл бұрын
This video on completeness is a (Dedekind) cut above the rest!
@rajivdixitbhaiifollower50554 жыл бұрын
Oooo yes! Now my life is completed
@arijeetsingh94444 жыл бұрын
This channel probably has the lowest dislike/like ratio! Way to go Dr. Peyam.
@toaj8684 жыл бұрын
Can you please explain where this proof breaks down if our range is restricted to Q? Is it that the Limsup and Liminf do not exist?
@drpeyam4 жыл бұрын
Pretty much, since a closed subset of a complete space is complete
@rajivdixitbhaiifollower50554 жыл бұрын
Great sir ! Well done
@MuPrimeMath4 жыл бұрын
lol that title
@dmytro_shum4 жыл бұрын
Sequence: sum 1/k (harmonic series) for k from 1 to n is not bounded. Is it a Cauchy sequence?
@dmytro_shum4 жыл бұрын
@@chemhwa I'm asking the author of the video
@dstigant4 жыл бұрын
No because it’s not bounded. Consecutive terms (Sn and Sn-1) will be arbitrarily close, but arbitrarily distant terms will not be arbitrarily close. That is , for any N and ep, there exists another integer larger than N, say M, Such that S(M)-S(N) > ep.
@dmytro_shum4 жыл бұрын
@@dstigant Another guy, which cant read ))) I am write that to interest him to make a video about that, because it is much more interesting sequence to use as example
@plaustrarius4 жыл бұрын
Yess! It is completed!!
@toaj8684 жыл бұрын
A space can be incomplete if we can get an element outside that space in the limit. Is there any other way in which spaces can be incomplete?
@drpeyam4 жыл бұрын
Any metric space can be completed, so no
@pocojoyo4 жыл бұрын
Dr Peyam, is this part of your Elementary Real Analysis course ? 1 or 2 ?
@drpeyam4 жыл бұрын
Yes, and 1
@pocojoyo4 жыл бұрын
@@drpeyam Thanks !
@B_A-tr4 жыл бұрын
So large amounts of people are cauchy
@dgrandlapinblanc2 жыл бұрын
Ok. Cool way. Thank you very much.
@f3ynman444 жыл бұрын
Where was this video when I took my Analysis Exam one month ago!? Still a good video though! 👍
@henrikfischbeck71986 ай бұрын
ure saying supremum and max as if they where the same. Also u say Q has holes, but then u say Z is complete... if it was lim min = lim max i would undetrstand but.. Uhm?... liminf(q)=sqrt(2)=limsup(q)...? Imagine a sequence of rationals getting closer and closer to sqrt2... the two numbers next to sqrt2 are rational ( because between two rationals is an irrational. and vice versa) so a sequence of rationals alternating around sqrt2 getting closer and closer have liminf(q)=sqrt(2)=limsup(q) ? like Q is dense in R so the smallest distance d(q,sqr2). but not if we change supp and inf for min and max..?
@shiina_mahiru_90674 жыл бұрын
I have already forgotten the entire proof from my analysis class 😂
@Galileo2pi4 жыл бұрын
Brilliant as always, mate, just on my birthday, thanks
@late72454 жыл бұрын
■ = the end
@coreymonsta75054 жыл бұрын
it's not surprising after you see it's just about technicalities regarding where elements lie
@vladimirbenitocardenas60124 жыл бұрын
This is an hard idea
@gabrielmendozallanes73234 жыл бұрын
UC Irvine is not complete without Dr. Peyam
@drpeyam4 жыл бұрын
Awww, I miss you!!!
@jkid11344 жыл бұрын
You're not building up to p-adics or something, are you? :)