Determining if this degree sequence is graphic

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SUMMARY

The degree sequence 3,3,2,2,2,2 is determined to be graphic using the Havel-Hakimi algorithm. The initial sum of the degrees is 16, which is even, allowing the application of the theorem. The sequence undergoes several transformations, including removing the highest degree and adjusting subsequent degrees, ultimately revealing that the sequence is indeed graphic when the algorithm is applied correctly. Misunderstandings in the reordering process of the sequence can lead to incorrect conclusions.

PREREQUISITES
  • Understanding of the Havel-Hakimi algorithm
  • Knowledge of degree sequences in graph theory
  • Ability to perform basic arithmetic operations
  • Familiarity with the concept of non-increasing sequences
NEXT STEPS
  • Study the Havel-Hakimi algorithm in detail
  • Practice determining graphic sequences with various degree sets
  • Explore other theorems related to graphic sequences, such as Erdős–Gallai theorem
  • Learn about applications of graphic sequences in network theory
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Students of graph theory, mathematicians, and anyone interested in understanding the properties of degree sequences and their graphical representations.

in the rye
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Homework Statement


Determine if the degree sequence 3,3,2,2,2,2 is graphic.

Homework Equations


Havel-Hakimi

The Attempt at a Solution


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Check to see if the sum is even:
3+3+2+2+2+2 = 16It is even, therefore apply Havel-Hakimi

3,3,2,2,2,2 -> remove the 3 and subtract the next 3 by 1
2,1,1,2,2 -> remove the 2 and subtract the next 2 by 1
0,0,2,2 -> reorder from largest to smallest
2,2,0,0 -> remove the 2 and subtract 1 from the next 2
1,-1,0 -> reached a negative, stop

Therefore the sequence is not graphic.

The solution says it is graphic and provides no explanation.

Am I misunderstanding Havel-Hakimi Theorem?
 
Last edited:
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Maybe I don't understand your steps. It looks to me like you did not reorder every time it was necessary to make the sequence non-increasing.
 
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FactChecker said:
Maybe I don't understand your steps. It looks to me like you did not reorder every time it was necessary to make the sequence non-increasing.
Facepalm. I completely missed that... I went back an re-looked at the problem before coming back to this post. It worked out when I applied the alogorithm correctly... thanks haha
 
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