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Shift graph

Shift 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 Shift graph rather than just read about it. In short: In graph theory, the shift graph Gn,k for n , k ∈ N , n > 2 k > 0 {\displaystyle n,k\in \mathbb {N} ,\ n>2k>0} is the graph whose vertices correspond to the ordered k {\displaystyle k} -tuples a = ( a 1 , a 2 , … , a k ) {\displaystyle a=(a_{1},a_{2},\dotsc ,a_{k})} with 1 ≤ a 1 < a 2 < ⋯ < a k ≤ n {\displaystyle 1\leq a_{1}<a_{2}<\cdots <a_{k}\leq n} and where two vertices a , b {\displaystyle a,b} are adjacent if…

Shift graph — main illustration
Shift graph — illustration

Key takeaways

  • Shift 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 Shift graph to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Shift graph from memory before moving on to harder problems.

Reference excerpt

In graph theory, the shift graph Gn,k for n , k ∈ N , n > 2 k > 0 {\displaystyle n,k\in \mathbb {N} ,\ n>2k>0} is the graph whose vertices correspond to the ordered k {\displaystyle k} -tuples a = ( a 1 , a 2 , … , a k ) {\displaystyle a=(a_{1},a_{2},\dotsc ,a_{k})} with 1 ≤ a 1 < a 2 < ⋯ < a k ≤ n {\displaystyle 1\leq a_{1}<a_{2}<\cdots <a_{k}\leq n} and where two vertices a , b {\displaystyle a,b} are adjacent if and only if a i = b i + 1 {\displaystyle a_{i}=b_{i+1}} or a i + 1 = b i {\displaystyle a_{i+1}=b_{i}} for all 1 ≤ i ≤ k − 1 {\displaystyle 1\leq i\leq k-1} . Shift graphs are triangle-free, and for fixed k {\displaystyle k} their chromatic number tend to infinity with n {\displaystyle n} . It is natural to enhance the shift graph G n , k {\displaystyle G_{n,k}} with the orientation a → b {\displaystyle a\to b} if a i + 1 = b i {\displaystyle a_{i+1}=b_{i}} for all 1 ≤ i ≤ k − 1 {\displaystyle 1\leq i\leq k-1} . Let G → n , k {\displaystyle {\overrightarrow {G}}_{n,k}} be the resulting directed shift graph. Note that G → n , 2 {\displaystyle {\overrightarrow {G}}_{n,2}} is the directed line graph of the transitive tournament corresponding to the identity permutation. Moreover, G → n , k + 1 {\displaystyle {\overrightarrow {G}}_{n,k+1}} is the directed line graph of G → n , k {\displaystyle {\overrightarrow {G}}_{n,k}} for all k ≥ 2 {\displaystyle k\geq 2} .

Further facts about shift graphs Odd cycles of G n , k {\displaystyle G_{n,k}} have length at least 2 k + 1 {\displaystyle 2k+1} , in particular G n , 2 {\displaystyle G_{n,2}} is triangle free. For fixed k ≥ 2 {\displaystyle k\geq 2} the asymptotic behaviour of the chromatic number of G n , k {\displaystyle G_{n,k}} is given by χ ( G n , k ) = ( 1 + o ( 1 ) ) log ⁡ log ⁡ ⋯ log ⁡ n {\displaystyle \chi (G_{n,k})=(1+o(1))\log \log \cdots \log n} where the logarithm function is iterated k − 1 {\displaystyle {\displaystyle k-1}} times. Further connections to the chromatic theory of graphs and digraphs have been established in. Shift graphs, in particular G n , 3 {\displaystyle G_{n,3}} also play a central role in the context of order dimension of interval orders.

Representation of shift graphs

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Shift graph

Start with the simplest possible case. Write down what Shift 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 Shift 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 Shift 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 Shift graph

In research
Shift 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 Shift 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
Shift graph is common in secondary-school and first-year university syllabi. It links to neighbouring topics Graph coloring, so understanding it makes those chapters shorter.
In everyday life
Look for Shift 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 Shift graph in 20 minutes

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

Frequently asked questions

What is Shift graph in simple terms?

In graph theory, the shift graph Gn,k for n , k ∈ N , n > 2 k > 0 {\displaystyle n,k\in \mathbb {N} ,\ n>2k>0} is the graph whose vertices correspond to the ordered k {\displaystyle k} -tuples a = ( a 1 , a 2 , … , a k ) {\displaystyle a=(a_{1},a_{2},\dotsc ,a_{k})} with 1 ≤ a 1 < a 2 < ⋯ < a k ≤ n…

Why does Shift 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 Shift 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 Shift graph.

Tags

  • Graph coloring

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