Ordinal numbers

Epsilon number

In mathematics, the epsilon numbers are a collection of transfinite numbers whose defining property is that they are fixed points of an exponential map. Consequently, they are not reachable from 0 via a finite series of applications of the chosen exponential map and of "weaker" operations like addition and multiplication. The original epsilon numbers were introduced by Georg Cantor in the context of ordinal arithmetic; they are the ordinal numbers ε that satisfy the equation in which ω is the smallest infinite ordinal. The least such ordinal is ε0 (pronounced epsilon nought or epsilon zero), which can be viewed as the "limit" obtained by transfinite recursion from a sequence of smaller limit ordinals: where sup is the supremum function, which is equivalent to set union in the case of the von Neumann representation of ordinals. Larger ordinal fixed points of the exponential map are indexed by ordinal subscripts, resulting in . The ordinal ε0 is still countable, as is any epsilon number whose index is countable (there exist uncountable ordinals, and uncountable epsilon numbers whose index is an uncountable ordinal). The smallest epsilon number ε0 appears in many induction proofs, because for many purposes, transfinite induction is only required up to ε0 (as in Gentzen's consistency proof and the proof of Goodstein's theorem). Its use by Gentzen to prove the consistency of Peano arithmetic, along with Gödel's second incompleteness theorem, show that Peano arithmetic cannot prove the well-foundedness of this ordering (it is in fact the least ordinal with this property, and as such, in proof-theoretic ordinal analysis, is used as a measure of the strength of the theory of Peano arithmetic). Many larger epsilon numbers can be defined using the Veblen function. A more general class of epsilon numbers has been identified by John Horton Conway and Donald Knuth in the surreal number system, consisting of all surreals that are fixed points of the base ω exponential map x → ωx. defined gamma numbers (see additively indecomposable ordinal) to be numbers γ>0 such that α+γ=γ whenever α<γ, and delta numbers (see multiplicatively indecomposable ordinals) to be numbers δ>1 such that αδ=δ whenever 0<α<δ, and epsilon numbers to be numbers ε>2 such that αε=ε whenever 1<α<ε. His gamma numbers are those of the form ωβ, and his delta numbers are those of the form ωωβ. (Wikipedia).

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Epsilon-Delta Definition of a Limit (Not Examinable)

This video introduces the formal definition for the limit of a function at a point. Presented by Norman Wildberger of the School of Mathematics and Statistics, UNSW.

From playlist Mathematics 1A (Calculus)

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Epsilon delta limit (Example 3): Infinite limit at a point

This is the continuation of the epsilon-delta series! You can find Examples 1 and 2 on blackpenredpen's channel. Here I use an epsilon-delta argument to calculate an infinite limit, and at the same time I'm showing you how to calculate a right-hand-side limit. Enjoy!

From playlist Calculus

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Calculus I - 1.2.3 The Epsilon-Delta Limit Definition

In this video we formalize the definition of a limit and explore strategies for determining the value of delta for a given or variable value of epsilon. Video Chapters: Intro 0:00 Informal to Formal Limit Definition 0:08 Finding Delta for Given Epsilon 3:50 Finding Delta in Terms of Epsil

From playlist Calculus I - Complete Course Under Construction

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ultimate introduction to the epsilon-delta definition of a limit

My most detailed introduction to the epsilon-delta definition of limits in calculus! The epsilon-delta definition of a limit is commonly considered the hardest topic in calculus 1 (it's also the important part at the beginning of real analysis). The best way to understand this precise defi

From playlist Epsilon-Delta definition of limits

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limits with epsilon-delta definition! (x^3 and 1/x examples)

Here's the easy way to write epsilon-delta proofs for limits. Usually, the epsilon-delta definition is taught in college calculus 1 (or real analysis in upper-division pure math but not on AP calculus). I think it is the hardest topic in calculus 1. Let me know what you think! Check out th

From playlist Epsilon-Delta definition of limits

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Ex: Limit Definition - Find Delta Values, Given Epsilon For a Limit

This video explains how to determine which delta values satisfy a given epsilon of a limit. http://mathispower4u.com

From playlist Limits

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Ex 2: Limit Definition - Determine Delta for an Arbitrary Epsilon (Quadratic)

This video explains how to determine an expression of delta for an arbitrary epsilon that can be used to prove a limit exists. http://mathispower4u.com

From playlist Limits

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limits with epsilon-delta definition! (linear, square root, and quadratic examples)

Here's the easy way to write epsilon-delta proofs for limits. Usually, the epsilon-delta definition is taught in college calculus 1 (or real analysis in upper-division pure math but not on AP calculus). I think it is the hardest topic in calculus 1. Let me know what you think! Check out th

From playlist Epsilon-Delta definition of limits

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Real Analysis | Open subsets of ℝ.

We give the standard definition of an open subset of the real numbers, give a few examples, and prove some classic results. Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespring.com/stores/michael-penn-math Personal Website: http://www.mich

From playlist Real Analysis

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Putnam Exam | 2011: B1

We present a solution to question B1 from the 2011 William Lowell Putnam Mathematics Competition. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/

From playlist Putnam Exam Solutions: A1/B1

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Real Analysis | The limit point of a set A⊆ℝ

We introduce the notion of the limit point of a set of real numbers and give a few examples. Further, we prove a classic result relating limit points of sets to limits of sequences. Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespring.com/

From playlist Real Analysis

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6. Szemerédi's graph regularity lemma I: statement and proof

MIT 18.217 Graph Theory and Additive Combinatorics, Fall 2019 Instructor: Yufei Zhao View the complete course: https://ocw.mit.edu/18-217F19 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62qauV_CpT1zKaGG_Vj5igX Szemerédi's graph regularity lemma is a powerful tool in

From playlist MIT 18.217 Graph Theory and Additive Combinatorics, Fall 2019

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Extremal Combinatorics with Po-Shen Loh 03/30 Mon

Carnegie Mellon University is protecting the community from the COVID-19 pandemic by running courses online for the Spring 2020 semester. This is the video stream for Po-Shen Loh’s PhD-level course 21-738 Extremal Combinatorics. Professor Loh will not be able to respond to questions or com

From playlist CMU PhD-Level Course 21-738 Extremal Combinatorics

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Debabrota Basu (6/17/20): Epsilon-net induced lazy witness complex for topological data analysis

Title: Epsilon-net induced lazy witness complex for efficient topological data analysis Abstract: Inefficient scalability of persistent homology computation on simplicial representations restrains practical application of TDA. The lazy witness complex economically defines an approximate r

From playlist AATRN 2020

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Ex 1: Limit Definition - Determine Delta for an Arbitrary Epsilon (Linear)

This video explains how to determine an expression of delta for an arbitrary epsilon that can be used to prove a limit exists. http://mathispower4u.com

From playlist Limits

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Discrete Structures: NFA with epsilon transitions to DFA

In this session we'll introduce NFAs with epsilon transitions and show how they can be transformed into DFAs. We will also go over my version of Thompson's constructions, use them to transform a regular expression in to an NFA, and then transform the resulting NFA into a DFA. This will giv

From playlist Discrete Structures

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Regular expressions and Non-Deterministic Finite State Automata (NFA)

A recap of converting regular expressions to non-deterministic finite state automata (NFA) with epsilon transitions, and then converting the NFA to a DFA. I used a simplified version of Thompson's Construction.

From playlist Discrete Structures

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Epsilon delta limit (Example 2)

In this video, I calculate the limit as x goes to 3 of x^2, using the epsilon-delta definition of a limit.

From playlist Calculus

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Sequences of complex numbers -- Complex Analysis 6

Real Analysis Playlist: https://www.youtube.com/watch?v=L-XLcmHwoh0&list=PL22w63XsKjqxqaF-Q7MSyeSG1W1_xaQoS ⭐Support the channel⭐ Patreon: https://www.patreon.com/michaelpennmath Merch: https://teespring.com/stores/michael-penn-math My amazon shop: https://www.amazon.com/shop/michaelpenn

From playlist Complex Analysis

Related pages

Fixed point (mathematics) | John Horton Conway | Ordinal analysis | Feferman–Schütte ordinal | Map (mathematics) | Uncountable set | Domain of a function | Limit ordinal | Transfinite induction | Transfinite number | Veblen function | Tree (graph theory) | Von Neumann cardinal assignment | Well-order | Large countable ordinal | Ordinal arithmetic | Equation | Cardinal number | Mathematics | Fixed-point lemma for normal functions | Mathematical induction | Normal function | On Numbers and Games | Additively indecomposable ordinal | Well-founded relation | Gentzen's consistency proof | Goodstein's theorem | Surreal number