ArticleslgStudy

mathematics

Linear Operators (book)

Linear Operators (book) is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Linear Operators (book) rather than just read about it. In short: Linear Operators is a three-volume textbook on the theory of linear operators, written by Nelson Dunford and Jacob T. Schwartz.

Key takeaways

  • Linear Operators (book) belongs to mathematics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Linear Operators (book) to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Linear Operators (book) from memory before moving on to harder problems.

Reference excerpt

Linear Operators is a three-volume textbook on the theory of linear operators, written by Nelson Dunford and Jacob T. Schwartz. The three volumes are (I) General Theory; (II) Spectral Theory, Self Adjoint Operators in Hilbert Space; and (III) Spectral Operators. The first volume was published in 1958, the second in 1963, and the third in 1971. All three volumes were reprinted by Wiley in 1988. Canonically cited as Dunford and Schwartz, the textbook has been referred to as "the definitive work" on linear operators. The work began as a written set of solutions to the problems for Dunford's graduate course in linear operators at Yale. Schwartz, a prodigy, had taken his undergraduate degree at Yale in 1948, age 18. In 1949 he began his graduate studies and enrolled in his course. Dunford recognised Schwartz's intelligence and they began a long collaboration, with Dunford acting as Schwartz's advisor for his dissertation Linear Elliptic Differential Operators. One fruit of their collaboration was the Dunford-Schwartz theorem. The work was originally intended to be a short introduction to functional analysis (the original material comprising what was published as Chapters 2, 4, 7 and part of 10 in Volume I) but the material ballooned. The work enjoyed funding from the Office of Naval Research and a popular joke at the time was that every nuclear submarine had a copy. William G. Bade and Robert G. Bartle were brought on as research assistants. Dunford retired shortly after finishing the final volume. Schwartz, however, went on to write similarly pathbreaking books in various other areas of mathematics. The book met with acclaim when published. It won the Leroy P. Steele Prize in 1981, awarded by the American Mathematical Society. In the citation for this prize, the committee observed "This monumental work of 2,592 pages must be the most comprehensive of its kind in mathematics ... A whole generation of analysts has been trained from it." Peter Lax remarked that it "contained everything known, and many things not yet known, on linear functional analysis." Béla Szőkefalvi-Nagy wrote in a review of the first volume: "the authors have created an extraordinarily important and valuable work that is distinguished in particular by its monumental completeness, clear organization, and attractive exposition". Gian-Carlo Rota, who was involved in checking the exercises, wrote that "the contrast between the uncompromising abstraction of the text and the incredible variety of the concrete examples in the exercises is immensely beneficial to any student learning mathematical analysis." Every chapter of the book ends with a section entitled "Notes and Remarks", giving historical background on the topic and informal discussion of related topics. The book contains more than a thousand exercises, wide-ranging and often difficult. One particularly difficult exercise was not solved until Dunford assigned it to a young Robert Langlands.

Notes

References

Worked examples

Example 1 — a first encounter with Linear Operators (book)

Start with the simplest possible case. Write down what Linear Operators (book) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Linear Operators (book) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Linear Operators (book) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Linear Operators (book)

In research
Linear Operators (book) appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Linear Operators (book) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Linear Operators (book) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Linear operators, Mathematics textbooks, so understanding it makes those chapters shorter.
In everyday life
Look for Linear Operators (book) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Linear Operators (book) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Linear Operators (book) means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Linear Operators (book) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Linear Operators (book) in simple terms?

Linear Operators is a three-volume textbook on the theory of linear operators, written by Nelson Dunford and Jacob T. Schwartz.

Why does Linear Operators (book) matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Linear Operators (book)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Linear Operators (book).

Tags

  • Linear operators
  • Mathematics textbooks

Keep exploring