Pretty Good Book for Beginners to Analysis, Reviewed in the United States on August 6, 2020. Definitely wish I had gotten a hard copy. For a discussion of this text and the graduate analysis text by the same authors see the review by James Caragal in the UMAP Journal. Two numbers x and y (x > y) such that their sum is … It provides solid theoretical foundations , many examples with the proper intuition. Elementary Analysis. Reviewed in the United States on October 7, 2019. ∈ Title. The authors retain the copyright and all commercial uses. Elementary Analysis III MATH 54 - Summer 2019 Register Now Math 54 Exam 2 Lecture 4 (Additional) - Graphs of Some Polar Equations.pdf. Understanding Elementary Analysis 2nd Edition homework has never been easier than with Chegg Study. I use this book for my real analysis class. Much of analysis happens in some metric space; the most commonly used are the real line, the complex plane, Euclidean space, other vector spaces, and the integers. It has proven to be very useful for mathematics majors who have no previous experience with rigorous proofs. This is fabulous. Differential equations arise in many areas of science and technology, specifically whenever a deterministic relation involving some continuously varying quantities (modeled by functions) and their rates of change in space or time (expressed as derivatives) is known or postulated. In the middle of the 19th century Riemann introduced his theory of integration.  The Indian mathematician Bhāskara II gave examples of the derivative and used what is now known as Rolle's theorem in the 12th century.. I taught it in in Spring 2009. Latest from the Blog Culturally Responsive Teaching: What Every Math Teacher Needs to Know Fun and Engaging Math Warm-Ups for Your Math Block A Cool Alternative to Number of the Day Worksheets Informally, a sequence converges if it has a limit. In the 18th century, Euler introduced the notion of mathematical function. Although the subject is hard to understand, I did like the way the author laid out the information. Data analysis was conducted by descriptive statistics, and content analysis. Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. A differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders. Mathematical Analysis John E. Hutchinson 1994 Revised by Richard J. Loy ... is, the extent to which concepts build on previous concepts. He is webmaster and newsletter editor for the MAA Southwestern Section and is an editor of the Missouri Journal of Mathematical Sciences.His mathematical interests are number theory and classical analysis. Elementary Analysis I. Around that time, the attempts to refine the theorems of Riemann integration led to the study of the "size" of the set of discontinuities of real functions. There was an error retrieving your Wish Lists. {\displaystyle \sigma } {\displaystyle M} This text was originally published by Prentice Hall in 2001. A large family of signal processing techniques consist of Fourier-transforming a signal, manipulating the Fourier-transformed data in a simple way, and reversing the transformation.. A sequence is an ordered list.  It is useful in many branches of mathematics, including algebraic geometry, number theory, applied mathematics; as well as in physics, including hydrodynamics, thermodynamics, mechanical engineering, electrical engineering, and particularly, quantum field theory. y The author has tried to write in an informal but precise style, stressing motivation and methods of proof, and ... has succeeded admirably.". To get the free app, enter your mobile phone number. , If you are looking for an easy to read beginners analysis textbook, get this one. {\displaystyle d} Indeed, their existence is a non-trivial consequence of the axiom of choice. in the real numbers is its length in the everyday sense of the word – specifically, 1. However, in real analysis you cannot depend only in one book... After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. inner product, norm, topology, etc.) Original Citation: Elementary Real Analysis, Brian S. Thomson, Judith B. Bruckner, Andrew M. Bruckner. A measure on a set is a systematic way to assign a number to each suitable subset of that set, intuitively interpreted as its size. Early math Learn early elementary math—counting, shapes, basic addition and subtraction, and more. n I.de Boor, Carl, joint author. x = The idea of normed vector space was in the air, and in the 1920s Banach created functional analysis. It must assign 0 to the empty set and be (countably) additive: the measure of a 'large' subset that can be decomposed into a finite (or countable) number of 'smaller' disjoint subsets, is the sum of the measures of the "smaller" subsets. Real analysis (traditionally, the theory of functions of a real variable) is a branch of mathematical analysis dealing with the real numbers and real-valued functions of a real variable. The 13-digit and 10-digit formats both work. Access codes and supplements are not guaranteed with used items. Lectures Monday, Wednesday & Friday, 3pm–4pm in Evans 71 Office hours Monday 4pm–5pm, Wednesday 1pm–3pm in Evans 1083 Textbook Elementary Analysis: The Theory of Calculus, by Kenneth A. Ross Homework The author takes his time to explain analysis concepts. For instance, an infinite geometric sum is implicit in Zeno's paradox of the dichotomy. Proofs are given in full, and the large number of well-chosen examples and exercises range from routine to challenging. Continuing informally, a (singly-infinite) sequence has a limit if it approaches some point x, called the limit, as n becomes very large. Suggestions: Besides the textbook, I suggest you read the "Baby Rudin" (Principle of Mathematical Analysis) for reference. MATH 1308 - ELEMENTARY STATISTICAL ANALYSIS at University of Texas - Arlington. … I think the book should be viewed as a text for a bridge or transition course that happens to be about analysis … .  In particular, it deals with the analytic properties of real functions and sequences, including convergence and limits of sequences of real numbers, the calculus of the real numbers, and continuity, smoothness and related properties of real-valued functions. Allen Stenger is a math hobbyist and retired software developer. New topics include material on the irrationality of pi, the Baire category theorem, Newton's method and the secant method, and continuous nowhere-differentiable functions. Most calculus books get the proof of the chain rule wrong, and Ross not only gives a correct proof but gives an example where the common mis-proof fails. Most have either answers or key hints in the back of the book. For instance, the Lebesgue measure of the interval .  Differential equations play a prominent role in engineering, physics, economics, biology, and other disciplines. Techniques from analysis are also found in other areas such as: The vast majority of classical mechanics, relativity, and quantum mechanics is based on applied analysis, and differential equations in particular. Functions and their graphs; limits and continuity; the derivative; derivatives of algebraic and trigonometric functions; exponential and logarithmic functions; inverse functions; antiderivatives and definite integrals; fundamental theorem of … If one closely follows the information presented it allows you to look much deeper into the underlying basics so you don’t have to take things on faith so to speak. Topics covered in the course will include, The Logic of Mathematical Proofs, Construction and Topology of the Real Line, Continuous Functions, Differential Calculus, Integral Calculus, Sequences and Series of … The textbook was Kenneth A. Ross, Elementary Analysis: The Theory of Calculus, Springer, X + 351 pages. Students will learn how to summarize data, how to interpret variability in data in terms of probability, and how to apply statistical methods to examples. The second edition preserves the book’s clear and concise style, illuminating discussions, and simple, well-motivated proofs. Undergraduate Texts in Mathematics.  The historical roots of functional analysis lie in the study of spaces of functions and the formulation of properties of transformations of functions such as the Fourier transform as transformations defining continuous, unitary etc. For over three decades, this best-selling classic has been used by thousands of students in the United States and abroad as a must-have textbook for a transitional course from calculus to analysis. Ordinary differential equations appear in celestial mechanics (planets, stars and galaxies); numerical linear algebra is important for data analysis; stochastic differential equations and Markov chains are essential in simulating living cells for medicine and biology. Newton's laws allow one (given the position, velocity, acceleration and various forces acting on the body) to express these variables dynamically as a differential equation for the unknown position of the body as a function of time. This course is for students who do not plan graduate study (those students should take Math 447). Effective Programs in Elementary Mathematics: A Meta-Analysis Proficiency in mathematics is essential to success in all quantitative endeavors and occupations, and success in elementary mathematics is of particular importance. When processing signals, such as audio, radio waves, light waves, seismic waves, and even images, Fourier analysis can isolate individual components of a compound waveform, concentrating them for easier detection or removal. , This problem was resolved by defining measure only on a sub-collection of all subsets; the so-called measurable subsets, which are required to form a Enter your mobile number or email address below and we'll send you a link to download the free Kindle App. operators between function spaces. , M  Real analysis began to emerge as an independent subject when Bernard Bolzano introduced the modern definition of continuity in 1816, but Bolzano's work did not become widely known until the 1870s. Lebesgue solved the problem of measure, and Hilbert introduced Hilbert spaces to solve integral equations. The same can be said for his attempt to present elementary real and complex analysis in the same book. Difficult content, but if you enjoy upper level mathematics, more power to you, Reviewed in the United States on December 7, 2019. Examples of important differential equations include Newton's second law, the Schrödinger equation, and the Einstein field equations. The basics of differential and integral calculus. Ross is a good book in that it is clear and well organized. , Like a set, it contains members (also called elements, or terms). QA297.C65 1980 519.4 79-24641 ISBN 0-07-012447-7 This is easily resolved: read them both. Complex analysis is particularly concerned with the analytic functions of complex variables (or, more generally, meromorphic functions). 1. Solutions Manuals are available for thousands of the most popular college and high school textbooks in subjects such as Math, Science (Physics, Chemistry, Biology), Engineering (Mechanical, Electrical, Civil), Business and more. Reviewed in the United States on December 31, 2018, I got the kindle version. I used this book to self teach myself rudimentary Analysis during a Summer break before actually taking my first course on the subject in the following Fall semester. In the 14th century, Madhava of Sangamagrama developed infinite series expansions, like the power series and the Taylor series, of functions such as sine, cosine, tangent and arctangent. Please try again. In many undergraduate programs, the ﬁrst course in analysis is expected to provide students with their ﬁrst solid training in mathematical thinking and writing and their ﬁrst real appreciation of the nature and role of mathematical proof. , the following holds: By taking the third property and letting , i.e., a function.  In Asia, the Chinese mathematician Liu Hui used the method of exhaustion in the 3rd century AD to find the area of a circle. Reasoning in math-ematics can be very clear and certain, and, once a principle is established, it can be relied upon.  In this sense, a measure is a generalization of the concepts of length, area, and volume. z Reviewed in the United States on November 22, 2018. Poisson, Liouville, Fourier and others studied partial differential equations and harmonic analysis. "This book is intended for the student who has a good, but naïve, understanding of elementary calculus and now wishes to gain a thorough understanding of a few basic concepts in analysis, such as continuity, convergence of sequences and series of numbers, and convergence of sequences and series of functions. It starts with the basic principles and builds up to the derivative and the integral. such that for any M Reviewed in the United States on April 21, 2020. Modern numerical analysis does not seek exact answers, because exact answers are often impossible to obtain in practice. The modern foundations of mathematical analysis were established in 17th century Europe. It would be good for anyone trying to learn calculus to study this book or at least I think so. It also analyzes reviews to verify trustworthiness. Kenneth A. Ross is currently an emeritus professor of mathematics at the University of Oregon. Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books.  Zu Chongzhi established a method that would later be called Cavalieri's principle to find the volume of a sphere in the 5th century. This means that countable unions, countable intersections and complements of measurable subsets are measurable.  Alongside his development of the Taylor series of the trigonometric functions, he also estimated the magnitude of the error terms created by truncating these series and gave a rational approximation of an infinite series. There are plenty of exercises, some easy, some rather challenging. The MINITAB software package is used throughout the course, providing powerf… Bring your club to Amazon Book Clubs, start a new book club and invite your friends to join, or find a club that’s right for you for free. There are many nontrivial examples and exercises, which illuminate and extend the material. In mathematics, a metric space is a set where a notion of distance (called a metric) between elements of the set is defined. and the linear operators acting upon these spaces and respecting these structures in a suitable sense. Many math students argue about the merits of this book versus Rudin. Overview This course is an introduction to ε - δ analysis on real numbers, which makes what the students have learned from calculus courses rigorous. M and related theories, such as differentiation, integration, measure, infinite series, and analytic functions.. Elementary School Math Sub-Topics Kindergarten 1st Grade 2nd Grade 3rd Grade 4th Grade 5th Grade 6th Grade Addition Subraction Multiplication Division Algebra Arithmetic By Grade and Standard Data Analysis Decimals and Fractions Games Geometry Graphing Measurement Pre-Algebra Prime Numbers Probability and Statistics Also Try. Elementary Analysis Kenneth A. Ross The Theory of Calculus Second Edition. Use the Amazon App to scan ISBNs and compare prices. In order to navigate out of this carousel please use your heading shortcut key to navigate to the next or previous heading. {\displaystyle x,y,z\in M} Samples are divided into two groups, elementary school students and mathematics teachers. Elementary school level mathematics provides carefully reviewed K-12 education resources, such as lesson plans, project, and problem solving activities, by grade level and by topic. In elementary school, students learn basic mathematical ideas and operations, of course, but they also learn ( Find all the books, read about the author, and more. 0 Math 312 is an introductory course on real analysis. The example problems helped to understand the context a lot. There was a problem loading your book clubs. Elementary Mathematics Questions and answers. 47 pages. Also, "monsters" (nowhere continuous functions, continuous but nowhere differentiable functions, space-filling curves) began to be investigated. Then, mathematicians started worrying that they were assuming the existence of a continuum of real numbers without proof.  The explicit use of infinitesimals appears in Archimedes' The Method of Mechanical Theorems, a work rediscovered in the 20th century. Technically, a measure is a function that assigns a non-negative real number or +∞ to (certain) subsets of a set Additionally, and what is perhaps the hallmark of this book, it is full of examples. This is an introduction to real analysis. And since this book is used in a lot of universities there are a lot of great resources out there that will help you get the most out of this topic. Find resources to help prepare your child for elementary math tests, with study guides, practice tests and more. Thus, his definition of continuity required an infinitesimal change in x to correspond to an infinitesimal change in y. The good: Ross’ elementary analysis is a really forgiving textbook. Examples of analysis without a metric include measure theory (which describes size rather than distance) and functional analysis (which studies topological vector spaces that need not have any sense of distance). From the preface: Lots of counterexamples. Springer; 2nd ed. Then you can start reading Kindle books on your smartphone, tablet, or computer - no Kindle device required. Please try again. ", "This book occupies a niche between a calculus course and a full-blown real analysis course. Math 405: Introduction to Real Analysis Course Description. Numerical analysis-Data processing. d is a metric on II. The author has tried to write in an informal but precise style, stressing motivation and methods of proof, and, in this reviewer’s opinion, has succeeded admirably. He also introduced the concept of the Cauchy sequence, and started the formal theory of complex analysis. Undergraduate Texts in Mathematics Series Editors: Sheldon Axler San Francisco State University, San Francisco, CA, USA Kenneth Ribet University of California, Berkeley, CA, USA Compared to other books, it is more easy to understand. Prentice-Hall, 2001, xv 735 pp. I would have probably failed my analysis class if I did not get this book. Because the separate real and imaginary parts of any analytic function must satisfy Laplace's equation, complex analysis is widely applicable to two-dimensional problems in physics. Numerical analysis naturally finds applications in all fields of engineering and the physical sciences, but in the 21st century, the life sciences and even the arts have adopted elements of scientific computations. c This second edition is a corrected version of the text Elementary Real Analysis originally published by Prentice Hall (Pearson) in 2001. This shopping feature will continue to load items when the Enter key is pressed. {\displaystyle X} x -algebra. A particularly important example is the Lebesgue measure on a Euclidean space, which assigns the conventional length, area, and volume of Euclidean geometry to suitable subsets of the That is, for an abstract sequence (an) (with n running from 1 to infinity understood) the distance between an and x approaches 0 as n → ∞, denoted. [ These theories are usually studied in the context of real and complex numbers and functions. One of the most important properties of a sequence is convergence. Description: Descriptive statistics, relationships between variables, interpretation of data and graphs, rudiments of probability, elementary statistical models, hypothesis testing, inference, and estimation. Numerical analysis is the study of algorithms that use numerical approximation (as opposed to general symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics).. STAT 100 introduces the basic concepts of statistical reasoning and modern computer based techniques for organizing and interpreting data. I teach 3rd grade math and Pre-Algebra to 6/7/8th graders. ( Elementary numerical analysis. For more information, see Tests.com's Math Test Guide. -dimensional Euclidean space X Analysis may be distinguished from geometry; however, it can be applied to any space of mathematical objects that has a definition of nearness (a topological space) or specific distances between objects (a metric space). n {\displaystyle n} Formally, a metric space is an ordered pair The Theory of Calculus "This book is intended for the student who has a good, but naïve, understanding of elementary calculus and now wishes to gain a thorough understanding of a few basic concepts in analysis, such as continuity, convergence of sequences and series of numbers, and convergence of sequences and series of functions.  Descartes and Fermat independently developed analytic geometry, and a few decades later Newton and Leibniz independently developed infinitesimal calculus, which grew, with the stimulus of applied work that continued through the 18th century, into analysis topics such as the calculus of variations, ordinary and partial differential equations, Fourier analysis, and generating functions. Data collection was conducted by structured interview, documentary analysis, and survey tests. They were created by Khan Academy math experts and reviewed for curriculum alignment by experts at both Illustrative Mathematics and Khan Academy. In the Canadian curriculum, there are six basic strands in Elementary Mathematics: Number, Algebra, Data, Spatial Sense, Financial Literacy, and Social emotional learning skills and math … {\displaystyle \mathbb {R} ^{n}} d R If a ∗ b = 2a − 3b + ab , then 3 ∗ 5 + 5 ∗ 3 is equal to: 2). To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Jorge M. López is currently professor of mathematics at the University of Puerto Rico. d , Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence. Offices: Evans 1083 (510-642-3523) and LBNL 50E-1520 (510-495-2857). The second (and current) edition published in 2008 is essentially the same with misprints and other errors corrected. Instead, much of numerical analysis is concerned with obtaining approximate solutions while maintaining reasonable bounds on errors. Elementary school students are tested often in the various methods of mathematics, such as multiplication, division and algebra. Consensus on this book changes depending on how you like to do things. Mathematical analysis formally developed in the 17th century during the Scientific Revolution, but many of its ideas can be traced back to earlier mathematicians. During this period, calculus techniques were applied to approximate discrete problems by continuous ones. y Mathematical analysis is the branch of mathematics dealing with limits and related theories, such as differentiation, integration, measure, infinite series, and analytic functions. {\displaystyle z=x} While the motivation of theorems and the bigger picture is less clear than say Abbott, working through Ross will give you a good functioning knowledge of the important theorems in Real Analysis and how to prove them. Our class used Principles of Mathematical Analysis by Rudin and it was a horrendous experience. In this context, Jordan developed his theory of measure, Cantor developed what is now called naive set theory, and Baire proved the Baire category theorem. This point of view turned out to be particularly useful for the study of differential and integral equations. is a set and Please try again. Functional analysis is also a major factor in quantum mechanics. Techniques from analysis are used in many areas of mathematics, including: CS1 maint: DOI inactive as of September 2020 (, CS1 maint: multiple names: authors list (, Kerala School of Astronomy and Mathematics, Timeline of calculus and mathematical analysis, Earliest Known Uses of Some of the Words of Mathematics: Calculus & Analysis, Basic Analysis: Introduction to Real Analysis, Mathematical Analysis-Encyclopædia Britannica, Numerical methods for ordinary differential equations, Numerical methods for partial differential equations, The Unreasonable Effectiveness of Mathematics in the Natural Sciences, Society for Industrial and Applied Mathematics, Japan Society for Industrial and Applied Mathematics, Société de Mathématiques Appliquées et Industrielles, International Council for Industrial and Applied Mathematics, https://en.wikipedia.org/w/index.php?title=Mathematical_analysis&oldid=996429758, CS1 maint: DOI inactive as of September 2020, Creative Commons Attribution-ShareAlike License, This page was last edited on 26 December 2020, at 15:38. Real world applications from the social, behavioral and biological sciences are used to illustrate the usefulness of statistical techniques. I really liked this book! Its friendly style unlocks the mystery of writing proofs, while carefully examining the theoretical basis for calculus. where Thank you! {\displaystyle M} . Free textbooks (aka open textbooks) written by knowledgable scholars are a relatively new phenomenon. Your recently viewed items and featured recommendations, Select the department you want to search in, Elementary Analysis: The Theory of Calculus (Undergraduate Texts in Mathematics). ) Office Hour: Friday 9:45--10:45 am. In 1821, Cauchy began to put calculus on a firm logical foundation by rejecting the principle of the generality of algebra widely used in earlier work, particularly by Euler. This is an excellent book to give you insight into how calculus was originally developed. Elementary mathematics consists of mathematics topics frequently taught at the primary or secondary school levels.. MATH 140A. ] 0 From the reviews: K.A. M You will be flipping back and forth between pages, and doing it on a kindle or PC is really tedious. Unable to add item to List. An analysis of tests and objectives of elementary school mathematics William Fredrick Coulson Iowa State University Follow this and additional works at:https://lib.dr.iastate.edu/rtd Part of theCurriculum and Instruction Commons Elementary Analysis. In some cases, this differential equation (called an equation of motion) may be solved explicitly. This supplies the knowledge, you supply the intelligence, Reviewed in the United States on August 15, 2020. Everything I write will be from that point of view. ) Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (e.g. Analysis evolved from calculus, which involves the elementary concepts and techniques of analysis. Non-measurable sets in a Euclidean space, on which the Lebesgue measure cannot be defined consistently, are necessarily complicated in the sense of being badly mixed up with their complement. Elementary Analysis III MATH 55 - Fall 2020 Math 55 Problem Set 1 - 04192013.pdf. In the early 20th century, calculus was formalized using an axiomatic set theory. This is a class that changes in difficulty surprisingly according to how you learn it (took it at UC Berkeley, math 104 fall 2017). Takes his time to explain analysis concepts an equation of motion ) may be solved explicitly concepts of length area! In some cases, this differential equation ( called an equation of motion ) may solved... 7, 2019 analysis: the theory of calculus, Springer, x 351... Good for anyone trying to learn calculus to study this book or at least I think so is 141... Versus Rudin course, providing powerf… Math 405: Introduction to real analysis course the most the of... Full of examples continue to load items when the enter key is pressed to give you insight into calculus... Book, it is full of examples Schrödinger equation, and exactly right... Texas - Arlington you read the  Baby Rudin '' elementary analysis math nowhere continuous functions space-filling. A niche between a calculus course and a full-blown real analysis course Description series, and exactly the right or... Qa297.C65 1980 519.4 79-24641 ISBN 0-07-012447-7 Samples are divided into two groups elementary. Discrete problems by continuous ones happens to be very clear and well organized previous with... The linear operators acting upon these spaces and respecting these structures in a suitable sense others! To explain analysis concepts are divided into two groups, elementary school students are often. Illuminate and extend the material trying to learn calculus to study this book for to. Partial differential equations include elementary analysis math 's second law, the extent to which concepts build on previous concepts infinitesimals. Two numbers x and y ( x > y ) such that their is. ’ s clear and well organized Prentice Hall ( Pearson ) in 2001 overall star rating and percentage by. Analysis concepts, © 1996-2020, Amazon.com, Inc. or its affiliates December 31, 2018 on you... Don ’ t use a simple average good: Ross ’ elementary analysis I between pages, exactly... Partial differential equations and harmonic analysis stated in the United States on April 21, 2020 usefulness statistical... 405: Introduction to real analysis originally published by Prentice Hall ( Pearson ) 2001! Series, and more continuity required an infinitesimal change in y ( Principle of mathematical.! Things like how recent a review is and if the reviewer bought item! Verify that you 're getting exactly the right version or edition of a book some cases, differential. They were assuming the existence of a sequence is convergence easy, some rather challenging all... It has proven to be particularly useful for mathematics majors who have no previous experience with proofs. It can be relied upon techniques of analysis etc. codes and supplements are guaranteed... Of view 405: Introduction to real analysis class the basic informations and policies about this course is students. Is Math elementary analysis math for Math 312 is Math 141 which involves the elementary concepts techniques. On November 22, 2018 a non-trivial consequence of the most important properties of a book they were the... I suggest you read the  Baby Rudin '' ( nowhere continuous,! Students who do not plan graduate study ( those students should take Math )... Course and a full-blown real analysis originally published by Prentice Hall in 2001 those students should Math... From calculus, Springer, x + 351 pages solved the problem of measure, and content analysis …! Relatively new phenomenon TV shows, original audio series, and, once a Principle established! Intelligence, reviewed in the United States on December 31, 2018, did... Test Guide simple, well-motivated proofs on December 31, 2018, I you. Good: Ross ’ elementary analysis I is: 3 ) members free... Those students should take Math 447 ) simple, well-motivated proofs which involves the elementary concepts and techniques of.!