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  1. big list - Conjectures that have been disproved with extremely large ...

    Jul 23, 2010 · The least counterexample known has order 142108547152020037174224853515625 and p = 5 p = 5. It is the same group that serves counterexample to the Hughes conjecture. Note, that for …

  2. What is an example of a proof by minimal counterexample?

    Nov 18, 2018 · If there aren't any counterexamples, the theorem is true, and we're done, so it's only the case where there is a counterexample that we have to deal with. This method of proof goes back (at …

  3. Advice on finding counterexamples - Mathematics Stack Exchange

    Apr 1, 2015 · I am reaching out for specific advice on how one should go about finding counterexamples. It seems almost every time I've ever attempted a "find a counterexample" problem, I have to cheat by …

  4. logic - Using truth tables to evaluate an argument and provide ...

    Dec 18, 2016 · These 3 statements aren't even related and it does not matter for a good counterexample. All that matters is that the atomic statements you choose for J, K and L are chosen …

  5. Using proof by contradiction and a counter example.

    Jul 13, 2017 · This $3$ is also a counterexample to the statement "all natural numbers are even". A proof by contradiction is a proof of a statement by assuming there is a counterexample and then …

  6. How are proofs formatted when the answer is a counterexample?

    Suppose it is asked: Prove or find a counterexample: the sum of two integers is odd The fact that 1 + 1 = 2 is a counterexample that disproves that statement. What is the proper format in which to

  7. discrete mathematics - How can I provide a counterexample for this ...

    Mar 9, 2016 · To give a counterexample you must interpret the argument formally, forgetting about lions & animals. The logical form is: All L's are A's, and all L's are M's; therefore all A's are M's. This is …

  8. "Almost true": non-trivial claims that have exactly one counterexample

    Oct 12, 2024 · Question: What are some non-trivial claims that have exactly one counterexample? Example 1: "There is no Pythagorean triple whose numbers are consecutive terms in a row of …

  9. reference request - Formal definition of “counterexample ...

    Jul 17, 2016 · What is the preferred formal definition of “counterexample” as in: zero is a counterexample for "every integer is either positive or negative". Where in the literature is the notion …

  10. notation - Is "proof by counterexample" a legitimate proof ...

    Apr 23, 2021 · A counterexample to a statement is a complete and valid proof that the statement is false. If I were to write up a proof of this statement, I would probably write something like the following: