enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Necessity and sufficiency - Wikipedia

    en.wikipedia.org/wiki/Necessity_and_sufficiency

    The assertion that Q is necessary for P is colloquially equivalent to "P cannot be true unless Q is true" or "if Q is false, then P is false". [9] [1] By contraposition, this is the same thing as "whenever P is true, so is Q". The logical relation between P and Q is expressed as "if P, then Q" and denoted "P ⇒ Q" (P implies Q).

  3. Vacuous truth - Wikipedia

    en.wikipedia.org/wiki/Vacuous_truth

    These examples, one from mathematics and one from natural language, illustrate the concept of vacuous truths: "For any integer x, if x > 5 then x > 3." [11] – This statement is true non-vacuously (since some integers are indeed greater than 5), but some of its implications are only vacuously true: for example, when x is the integer 2, the statement implies the vacuous truth that "if 2 > 5 ...

  4. List of paradoxes - Wikipedia

    en.wikipedia.org/wiki/List_of_paradoxes

    Interesting number paradox: The first number that can be considered "dull" rather than "interesting" becomes interesting because of that fact. Potato paradox : If potatoes consisting of 99% water dry until they are 98% water, they lose 50% of their weight.

  5. Material conditional - Wikipedia

    en.wikipedia.org/wiki/Material_conditional

    For instance, counterfactual conditionals would all be vacuously true on such an account, when in fact some are false. [8] In the mid-20th century, a number of researchers including H. P. Grice and Frank Jackson proposed that pragmatic principles could explain the discrepancies between natural language conditionals and the material conditional.

  6. Burnside problem - Wikipedia

    en.wikipedia.org/wiki/Burnside_problem

    The existence of the free Burnside group and its uniqueness up to an isomorphism are established by standard techniques of group theory. Thus if G is any finitely generated group of exponent n, then G is a homomorphic image of B(m, n), where m is the number of generators of G. The Burnside problem for groups with bounded exponent can now be ...

  7. Markov's principle - Wikipedia

    en.wikipedia.org/wiki/Markov's_principle

    In predicate logic, a predicate P over some domain is called decidable if for every x in the domain, either P(x) holds, or the negation of P(x) holds. This is not trivially true constructively. Markov's principle then states: For a decidable predicate P over the natural numbers, if P cannot be false for all natural numbers n, then it is true ...

  8. Erdős–Straus conjecture - Wikipedia

    en.wikipedia.org/wiki/Erdős–Straus_conjecture

    In particular, if the Erdős–Straus conjecture itself (the case =) is false, then the number of counterexamples grows only sublinearly. Even more strongly, for any fixed k {\displaystyle k} , only a sublinear number of values of n {\displaystyle n} need more than two terms in their Egyptian fraction expansions. [ 17 ]

  9. Pigeonhole principle - Wikipedia

    en.wikipedia.org/wiki/Pigeonhole_principle

    Since 10 is greater than 9, the pigeonhole principle says that at least one hole has more than one pigeon. (The top left hole has 2 pigeons.) In mathematics, the pigeonhole principle states that if n items are put into m containers, with n > m, then at least one container must contain more than one item. [1]