computer science

Richard Leibler

Richard Leibler is a computer science 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 Richard Leibler rather than just read about it. In short: Richard A. Leibler (; March 18, 1914 – October 25, 2003) was an American mathematician and cryptanalyst.

Key takeaways

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

Reference excerpt

Richard A. Leibler (; March 18, 1914 – October 25, 2003) was an American mathematician and cryptanalyst. Richard Leibler was born in March 1914. He received his A.M. in mathematics from Northwestern University and his Ph.D. from the University of Illinois in 1939. While working at the National Security Agency, he and Solomon Kullback formulated the Kullback–Leibler divergence, a measure of similarity between probability distributions which has found important applications in information theory and cryptology. Leibler is also credited by the NSA as having opened up "new methods of attack" in the celebrated VENONA code-breaking project during 1949-1950; this may be a reference to his joint paper with Kullback, which was published in the open literature in 1951 and was immediately noted by Soviet cryptologists. He was director of the Communications Research Division at the Institute for Defense Analyses from 1962 to 1977, during which he was the boss of Jim Simons. He was inducted into the NSA Hall of Honor for his efforts against the VENONA code.

References

External links Biography in NSA's Cryptologic Hall of Honor.

Illustrations

Worked examples

Example 1 — a first encounter with Richard Leibler

Start with the simplest possible case. Write down what Richard Leibler claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, 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 Richard Leibler 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 Richard Leibler 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 Richard Leibler

In research: Richard Leibler appears in computer science 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 Richard Leibler 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: Richard Leibler is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1914 births, 2003 deaths, 20th-century American mathematicians, so understanding it makes those chapters shorter.
In everyday life: Look for Richard Leibler 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.

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How to study Richard Leibler in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Richard Leibler means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Richard Leibler out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Richard Leibler in simple terms?

Richard A. Leibler (; March 18, 1914 – October 25, 2003) was an American mathematician and cryptanalyst.

Why does Richard Leibler matter?

Because it connects several computer science 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 Richard Leibler?

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 Richard Leibler.