astronomy

Max Kelly

Max Kelly is a astronomy 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 Max Kelly rather than just read about it. In short: Gregory Maxwell "Max" Kelly (5 June 1930 – 26 January 2007) was an Australian mathematician who worked on category theory. Biography Kelly was born in Bondi, New South Wales, Australia, on 5 June 1930.

Key takeaways

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

Reference excerpt

Gregory Maxwell "Max" Kelly (5 June 1930 – 26 January 2007) was an Australian mathematician who worked on category theory.

Biography Kelly was born in Bondi, New South Wales, Australia, on 5 June 1930. He obtained his PhD at Cambridge University in homological algebra in 1957, publishing his first paper in that area in 1959, Single-space axioms for homology theory. He taught in the Pure Mathematics department at the University of Sydney from 1957 to 1966, rising from lecturer to reader. During 1963–1965 he was a visiting fellow at Tulane University and the University of Illinois, where with Samuel Eilenberg he formalized and developed the notion of an enriched category based on intuitions then in the air about making the homsets of a category just as abstract as the objects themselves. He subsequently developed the notion in considerably more detail in his 1982 monograph Basic Concepts of Enriched Category Theory. Let V {\displaystyle {\cal {V}}} be a monoidal category, and denote by V {\displaystyle {\cal {V}}} -Cat the category of V {\displaystyle {\cal {V}}} -enriched categories. Among other things, Kelly showed that V {\displaystyle {\cal {V}}} -Cat has all weighted limits and colimits even when V {\displaystyle {\cal {V}}} does not have all ordinary limits and colimits. He also developed the enriched counterparts of Kan extensions, density of the Yoneda embedding, and essentially algebraic theories. In 1967 Kelly was appointed Professor of Pure Mathematics at the University of New South Wales. In 1972 he was elected a Fellow of the Australian Academy of Science. He returned to the University of Sydney in 1973, serving as Professor of Mathematics until his retirement in 1992. In 2001 he was awarded the Australian government's Centenary Medal. He continued to participate in the department as professorial fellow and professor emeritus until his death at age 76 on 26 January 2007. Kelly worked on many other aspects of category theory besides enriched categories, both individually and in a number of collaborations. His PhD students include Ross Street.

References

External links Max Kelly's Perpetual Web Page: a memorial page set up by Kelly's son Simon Kelly. "In Memory of Max Kelly": a post at The n-Category Café, containing praise from his fellow mathematicians G. M. Kelly at DBLP Bibliography Server

Worked examples

Example 1 — a first encounter with Max Kelly

Start with the simplest possible case. Write down what Max Kelly claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, 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 Max Kelly 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 Max Kelly 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 Max Kelly

In research: Max Kelly appears in astronomy 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 Max Kelly 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: Max Kelly is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1930 births, 2007 deaths, Academic staff of the University of New South Wales, so understanding it makes those chapters shorter.
In everyday life: Look for Max Kelly 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 Max Kelly in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Max Kelly 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 Max Kelly out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Max Kelly in simple terms?

Gregory Maxwell "Max" Kelly (5 June 1930 – 26 January 2007) was an Australian mathematician who worked on category theory. Biography Kelly was born in Bondi, New South Wales, Australia, on 5 June 1930.

Why does Max Kelly matter?

Because it connects several astronomy 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 Max Kelly?

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 Max Kelly.