Search results
Results from the WOW.Com Content Network
In mathematics and logic, the term "uniqueness" refers to the property of being the one and only object satisfying a certain condition. [1] This sort of quantification is known as uniqueness quantification or unique existential quantification, and is often denoted with the symbols "∃!" [2] or "∃ =1". For example, the formal statement
(In particular, the sentence explicitly specifies its domain of discourse to be the natural numbers, not, for example, the real numbers.) This particular example is true, because 5 is a natural number, and when we substitute 5 for n , we produce the true statement 5 × 5 = 25 {\displaystyle 5\times 5=25} .
A truth table has one column for each input variable (for example, A and B), and one final column showing all of the possible results of the logical operation that the table represents (for example, A XOR B). Each row of the truth table contains one possible configuration of the input variables (for instance, A=true, B=false), and the result of ...
De Morgan's laws represented with Venn diagrams.In each case, the resultant set is the set of all points in any shade of blue. In propositional logic and Boolean algebra, De Morgan's laws, [1] [2] [3] also known as De Morgan's theorem, [4] are a pair of transformation rules that are both valid rules of inference.
A formula in first-order logic with no free variable occurrences is called a first-order sentence. These are the formulas that will have well-defined truth values under an interpretation. For example, whether a formula such as Phil(x) is true must depend on what x represents.
Each kind of quantification defines a corresponding closure operator on the set of formulas, by adding, for each free variable x, a quantifier to bind x. [9] For example, the existential closure of the open formula n>2 ∧ x n +y n =z n is the closed formula ∃n ∃x ∃y ∃z (n>2 ∧ x n +y n =z n); the latter formula, when interpreted over ...
Logical equality is a logical operator that compares two truth values, or more generally, two formulas, such that it gives the value True if both arguments have the same truth value, and False if they are different.
An atomic formula is a formula that contains no logical connectives nor quantifiers, or equivalently a formula that has no strict subformulas. The precise form of atomic formulas depends on the formal system under consideration; for propositional logic, for example, the atomic formulas are the propositional variables.