science

Wells graph

Wells graph is a 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 Wells graph rather than just read about it. In short: The Wells graph is the unique distance-regular graph with intersection array ( 5 , 4 , 1 , 1 ; 1 , 1 , 4 , 5 ) . {\displaystyle (5,4,1,1;1,1,4,5).} Its spectrum is 5 1 5 8 1 10 ( − 5 ) 8 ( − 3 ) 5 {\displaystyle 5^{1}{\sqrt {5}}^{8}1^{10}(-{\sqrt {5}})^{8}(-3)^{5}} . Its queue number is 3 and an upper bound on its book thickness is 5.

Key takeaways

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

Reference excerpt

The Wells graph is the unique distance-regular graph with intersection array ( 5 , 4 , 1 , 1 ; 1 , 1 , 4 , 5 ) . {\displaystyle (5,4,1,1;1,1,4,5).}

Its spectrum is

5 1 5 8 1 10 ( − 5 ) 8 ( − 3 ) 5 {\displaystyle 5^{1}{\sqrt {5}}^{8}1^{10}(-{\sqrt {5}})^{8}(-3)^{5}} . Its queue number is 3 and an upper bound on its book thickness is 5.

References

External links A.E. Brouwer's website: The Armanios-Wells graph

Illustrations

Worked examples

Example 1 — a first encounter with Wells graph

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

In research: Wells graph appears in 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 Wells graph 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: Wells graph is common in secondary-school and first-year university syllabi. It links to neighbouring topics Graph theory stubs, Individual graphs, Regular graphs, so understanding it makes those chapters shorter.
In everyday life: Look for Wells graph 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 Wells graph in 20 minutes

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

Frequently asked questions

What is Wells graph in simple terms?

The Wells graph is the unique distance-regular graph with intersection array ( 5 , 4 , 1 , 1 ; 1 , 1 , 4 , 5 ) . {\displaystyle (5,4,1,1;1,1,4,5).} Its spectrum is 5 1 5 8 1 10 ( − 5 ) 8 ( − 3 ) 5 {\displaystyle 5^{1}{\sqrt {5}}^{8}1^{10}(-{\sqrt {5}})^{8}(-3)^{5}} . Its queue number is 3 and an up…

Why does Wells graph matter?

Because it connects several 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 Wells graph?

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 Wells graph.