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Any involution is a bijection.. The identity map is a trivial example of an involution. Examples of nontrivial involutions include negation (x ↦ −x), reciprocation (x ↦ 1/x), and complex conjugation (z ↦ z) in arithmetic; reflection, half-turn rotation, and circle inversion in geometry; complementation in set theory; and reciprocal ciphers such as the ROT13 transformation and the ...
A literal is a propositional variable or the negation of a propositional variable. Two literals are said to be complements if one is the negation of the other (in the following, is taken to be the complement to ). The resulting clause contains all the literals that do not have complements. Formally:
As a further example, negation can be defined in terms of NAND and can also be defined in terms of NOR. Algebraically, classical negation corresponds to complementation in a Boolean algebra, and intuitionistic negation to pseudocomplementation in a Heyting algebra. These algebras provide a semantics for classical and intuitionistic logic.
A generalization of the class of Horn formulas is that of renameable-Horn formulae, which is the set of formulas that can be placed in Horn form by replacing some variables with their respective negation. For example, (x 1 ∨ ¬x 2) ∧ (¬x 1 ∨ x 2 ∨ x 3) ∧ ¬x 1 is not a Horn formula, but can be renamed to the Horn formula (x 1 ∨ ¬x ...
In mathematics, an involute (also known as an evolvent) is a particular type of curve that is dependent on another shape or curve. An involute of a curve is the locus of a point on a piece of taut string as the string is either unwrapped from or wrapped around the curve.
Ree got this recipe from her mom's trusty recipe binder years ago and notes "It's basically the best dessert of all time." The secret is a can of Mountain Dew and a lot of butter, of course.
Negation normal form is not a canonical form: for example, () and () are equivalent, and are both in negation normal form. In classical logic and many modal logics , every formula can be brought into this form by replacing implications and equivalences by their definitions, using De Morgan's laws to push negation inwards, and eliminating double ...
NEW YORK (Reuters) -Robert F. Kennedy Jr, the former independent presidential candidate, is reviewing candidate resumes for the top jobs at the U.S. government's health agencies in Donald Trump's ...