Convergence (mathematics) | Sequences and series | Metric geometry | Abstract algebra | Topology
In mathematics, a Cauchy sequence (French pronunciation: [koʃi]; English: /ˈkoʊʃiː/ KOH-shee), named after Augustin-Louis Cauchy, is a sequence whose elements become arbitrarily close to each other as the sequence progresses. More precisely, given any small positive distance, all but a finite number of elements of the sequence are less than that given distance from each other. It is not sufficient for each term to become arbitrarily close to the preceding term. For instance, in the sequence of square roots of natural numbers: the consecutive terms become arbitrarily close to each other:However, with growing values of the index n, the terms become arbitrarily large. So, for any index n and distance d, there exists an index m big enough such that (Actually, any suffices.) As a result, despite how far one goes, the remaining terms of the sequence never get close to each other; hence the sequence is not Cauchy. The utility of Cauchy sequences lies in the fact that in a complete metric space (one where all such sequences are known to converge to a limit), the criterion for convergence depends only on the terms of the sequence itself, as opposed to the definition of convergence, which uses the limit value as well as the terms. This is often exploited in algorithms, both theoretical and applied, where an iterative process can be shown relatively easily to produce a Cauchy sequence, consisting of the iterates, thus fulfilling a logical condition, such as termination. Generalizations of Cauchy sequences in more abstract uniform spaces exist in the form of Cauchy filters and Cauchy nets. (Wikipedia).
Cauchy Sequence In this video, I define one of the most important concepts in analysis: Cauchy sequences. Those are sequences which "crowd" together, without necessarily going to a limit. Later, we'll see what implications they have in analysis. Check out my Sequences Playlist: https://w
From playlist Sequences
Proof that the Sequence {1/n} is a Cauchy Sequence
Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys Proof that the Sequence {1/n} is a Cauchy Sequence
From playlist Cauchy Sequences
Intro to Cauchy Sequences and Cauchy Criterion | Real Analysis
What are Cauchy sequences? We introduce the Cauchy criterion for sequences and discuss its importance. A sequence is Cauchy if and only if it converges. So Cauchy sequences are another way of characterizing convergence without involving the limit. A sequence being Cauchy roughly means that
From playlist Real Analysis
If A Sequence is Cauchy in Space it's Component Sequences are Cauchy Proof
If A Sequence is Cauchy in Space it's Component Sequences are Cauchy Proof If you enjoyed this video please consider liking, sharing, and subscribing. You can also help support my channel by becoming a member https://www.youtube.com/channel/UCr7lmzIk63PZnBw3bezl-Mg/join Thank you:)
From playlist Cauchy Sequences
Proof: Sequence (1/n) is a Cauchy Sequence | Real Analysis Exercises
We prove the sequence {1/n} is Cauchy using the definition of a Cauchy sequence! Since (1/n) converges to 0, it shouldn't be surprising that the terms of (1/n) get arbitrarily close together, and as we have proven (or will prove, depending where you're at), convergence and Cauchy-ness are
From playlist Real Analysis Exercises
Completeness In this video, I define the notion of a complete metric space and show that the real numbers are complete. This is a nice application of Cauchy sequences and has deep consequences in topology and analysis Cauchy sequences: https://youtu.be/ltdjB0XG0lc Check out my Sequences
From playlist Sequences
How to Prove a Sequence is a Cauchy Sequence Advanced Calculus Proof with {n^2/(n^2 + 1)}
Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys How to Prove a Sequence is a Cauchy Sequence Advanced Calculus Proof with {n^2/(n^2 + 1)}
From playlist Cauchy Sequences
Real Analysis: Let {x_n} be a sequence of real numbers such that |x_n| is less than (3n^2-2)/(4n^3 + n^2 + 3). Prove that {x_n} is a Cauchy sequence.
From playlist Real Analysis
Math 101 Fall 2017 103017 Introduction to Cauchy Sequences
Definition of a Cauchy sequence. Convergent sequences are Cauchy. Cauchy sequences are not necessarily convergent. Cauchy sequences are bounded. Completeness of the real numbers (statement).
From playlist Course 6: Introduction to Analysis (Fall 2017)
Mod-01 Lec-05 Examples of Norms,Cauchy Sequence and Convergence, Introduction to Banach Spaces
Advanced Numerical Analysis by Prof. Sachin C. Patwardhan,Department of Chemical Engineering,IIT Bombay.For more details on NPTEL visit http://nptel.ac.in
From playlist IIT Bombay: Advanced Numerical Analysis | CosmoLearning.org
Metric Spaces - Lectures 11 & 12: Oxford Mathematics 2nd Year Student Lecture
For the first time we are making a full Oxford Mathematics Undergraduate lecture course available. Ben Green's 2nd Year Metric Spaces course is the first half of the Metric Spaces and Complex Analysis course. This is the 6th of 11 videos. The course is about the notion of distance. You ma
From playlist Oxford Mathematics Student Lectures - Metric Spaces
Metric Spaces - Lectures 13 & 14: Oxford Mathematics 2nd Year Student Lecture
For the first time we are making a full Oxford Mathematics Undergraduate lecture course available. Ben Green's 2nd Year Metric Spaces course is the first half of the Metric Spaces and Complex Analysis course. This is the 7th of 11 videos. The course is about the notion of distance. You ma
From playlist Oxford Mathematics Student Lectures - Metric Spaces
Uniform Continuity and Cauchy In this video, I answer a really interesting question about continuous functions: If sn is a Cauchy sequence and f is a continuous function, then is f(sn) Cauchy as well? Surprisingly this has to do with uniform continuity. Watch this video to find out why!
From playlist Limits and Continuity
Here is fundamental mathematical result in mathematics, namely: any metric space, no matter how crazy it is, can be completed. After watching this video, it should be no surprise that the rational numbers can be completed to get the real numbers. The proof itself is very neat and kind of m
From playlist Topology
Proof: Cauchy Sequences are Convergent | Real Analysis
We prove every Cauchy sequence converges. To do this we use the fact that Cauchy sequences are bounded, then apply the Bolzano Weierstrass theorem to get a convergent subsequence, then we use Cauchy and subsequence properties to prove the sequence converges to that same limit as the subseq
From playlist Real Analysis
Proof: Convergent Sequences are Cauchy | Real Analysis
We prove that every convergent sequence is a Cauchy sequence. Convergent sequences are Cauchy, isn't that neat? This is the first half of our effort to prove that a sequence converges if and only if it is Cauchy. Next we will have to prove that Cauchy sequences are convergent! Subscribe fo
From playlist Real Analysis