Is NP-Complete Harder to Solve than NP-Hard?

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Discussion Overview

The discussion revolves around the comparative difficulty of NP-Complete and NP-Hard problems, exploring their definitions and implications in computational complexity theory. Participants examine the relationships between these classes of problems and their respective computational resources.

Discussion Character

  • Debate/contested, Technical explanation

Main Points Raised

  • One participant questions whether NP-Complete problems are more difficult to solve than NP-Hard problems, noting that NP-Complete problems are in NP and NP-Hard, while not all NP-Hard problems are in NP.
  • Another participant clarifies that NP-Hard is a strict superset of NP-Complete, indicating that some NP-Hard problems, such as the halting problem, are not in NP.
  • A different viewpoint suggests that NP-Hard problems that are not NP-Complete are generally 'harder' due to their higher resource requirements, which may include memory, time, alternation, or randomness.
  • One participant mentions that NP-Hard problems might be impossible to solve in general and explains that the class NP includes problems that are easier than its toughest problems, implying that problems outside NP are harder than those within it.
  • A suggestion is made to post such questions in the Programming forum, indicating a perspective on the appropriate categorization of the topic.

Areas of Agreement / Disagreement

Participants express differing views on the difficulty comparison between NP-Complete and NP-Hard problems, with no consensus reached on which class is definitively harder.

Contextual Notes

Participants discuss the implications of problem classifications and their relationships but do not resolve the complexities surrounding definitions and computational resources.

jetoso
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I have a question. Is the class of problems NP-Complete more difficult to solve than the class of problems NP-Hard?

I mean, NP-Complete problems are in NP, and also are NP-Hard, but not all NP-Hard problems are in NP... How to tell which one is more difficult to solve?
 
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The set of problems that are NP-hard is a strict superset of the problems that are NP-complete. Some problems (like the halting problem) are NP-hard, but not in NP.
 
NP-Hard problems that are not NP-Complete are 'harder' than NP problems, in general, in that they take up more computational resources of some type: memory, time, alternation, randomness, etc.
 
Or as Nate mentioned, NP-hard problems might be impossible to solve in general. You can tell the difference in difficulty between NP-hard and NP-complete problems because the class NP includes everything easier than its "toughest" problems--if a problem is not in NP, it is harder than all the problems in NP.

By the way, would you post things like this in the future in the Programming forum, as it is a computer science question?
 
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