- Existential quantification (Wikipedia)
In predicate logic, an existential quantification is a type of quantifier, a logical constant which is interpreted as “there exists”, “there is at least one”, or “for some”. It is usually denoted by the logical operator symbol ∃, which, when used together with a predicate variable, is called an existential quantifier ("∃x" or “∃(x)” or “(∃x)”). Existential quantification is distinct from universal quantification (“for all”), which asserts that the property or relation holds for all members of the domain. Some sources use the term existentialization to refer to existential quantification.
- Hill (Wikipedia)
A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as mountains. Hills fall under the category of slope landforms.
