astronomy

Jeannette Janssen

Jeannette Janssen 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 Jeannette Janssen rather than just read about it. In short: Jeannette Catharina Maria Janssen is a Dutch and Canadian mathematician whose research concerns graph theory and the theory of complex networks. She is a professor of mathematics at Dalhousie University, the chair of the Dalhousie Department of Mathematics and Statistics, and the chair of the Activity Group on Discrete Mathematics of the Society for Industrial and Applied Mathematics.

Key takeaways

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

Reference excerpt

Jeannette Catharina Maria Janssen is a Dutch and Canadian mathematician whose research concerns graph theory and the theory of complex networks. She is a professor of mathematics at Dalhousie University, the chair of the Dalhousie Department of Mathematics and Statistics, and the chair of the Activity Group on Discrete Mathematics of the Society for Industrial and Applied Mathematics.

Education and career Janssen earned a master's degree at the Eindhoven University of Technology in 1988. She completed her Ph.D. at Lehigh University in 1993. Her dissertation, Even and Odd Latin Squares, concerned Latin squares and was supervised by Edward F. Assmus Jr. From 1988 to 1990 Janssen was a lecturer at the Universidad de Guanajuato in Mexico. After completing her Ph.D., she became a postdoctoral researcher jointly at the Laboratoire de Combinatoire et d’Informatique Mathématique of Université du Québec à Montréal and at Concordia University. She took a position as a lecturer and research associate at the London School of Economics in 1995, and moved to Acadia University in 1997 before taking her present position at Dalhousie University. At Dalhousie, she was named department chair in 2016, becoming the first female chair of the mathematics department.

Service Janssen directed the Atlantic Association for Research in the Mathematical Sciences from 2011 to 2016, and chairs its board of directors. She was elected as chair of the Activity Group on Discrete Mathematics (SIAG-DM) of the Society for Industrial and Applied Mathematics (SIAM) for the 2021–2022 term.

Research In a 1993 paper, Janssen solved the unbalanced case of the Dinitz conjecture, showing that any partial Latin rectangle could be extended to a full rectangle. The problem is equivalent to list edge-coloring of complete bipartite graphs, and her solution was based on earlier work on list coloring by Noga Alon and Michael Tarsi. Janssen's work "surprised even many of the experts", and was considered to be "great progress" on the Dinitz conjecture. The remaining case of the conjecture for squares (balanced complete bipartite graphs) was proven a year later by Fred Galvin.

References

External links Home page Jeannette Janssen publications indexed by Google Scholar

Worked examples

Example 1 — a first encounter with Jeannette Janssen

Start with the simplest possible case. Write down what Jeannette Janssen 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 Jeannette Janssen 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 Jeannette Janssen 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 Jeannette Janssen

In research: Jeannette Janssen 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 Jeannette Janssen 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: Jeannette Janssen is common in secondary-school and first-year university syllabi. It links to neighbouring topics Academic staff of Acadia University, Academic staff of Dalhousie University, Academic staff of Universidad de Guanajuato, so understanding it makes those chapters shorter.
In everyday life: Look for Jeannette Janssen 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 Jeannette Janssen in 20 minutes

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

Frequently asked questions

What is Jeannette Janssen in simple terms?

Why does Jeannette Janssen 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 Jeannette Janssen?

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 Jeannette Janssen.