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Every infinite set which can be enumerated by natural numbers is the same size (cardinality) as N, and is said to be countable. Examples of countably infinite sets are the natural numbers, the even numbers, the prime numbers, and also all the rational numbers, i.e., the fractions.
To investigate the left distributivity of set subtraction over unions or intersections, consider how the sets involved in (both of) De Morgan's laws are all related: () = = () always holds (the equalities on the left and right are De Morgan's laws) but equality is not guaranteed in general (that is, the containment might be strict).
Most sets commonly encountered are not members of themselves. Let us call a set "normal" if it is not a member of itself, and "abnormal" if it is a member of itself. Clearly every set must be either normal or abnormal. For example, consider the set of all squares in a plane. This set is not itself a square in the plane, thus it is not a member ...
Environmental studies (EVS or EVST) is a multidisciplinary academic field which systematically studies human interaction with the environment.Environmental studies connects principles from the physical sciences, commerce/economics, the humanities, [1] and social sciences [2] to address complex contemporary environmental issues.
Non-fiction environmental books may, for example, be the products of scholarly or journalistic work. The books in this list include fields and styles such as anthropology , conservation science , ecology , environmental history , lifestyle, and memoirs .
Environmental studies connects principles from the physical sciences, commerce/economics, the humanities, and social sciences to address complex contemporary environmental issues. It is a broad field of study that includes the natural environment, the built environment, and the relationship between them.
The balance of nature, also known as ecological balance, is a theory that proposes that ecological systems are usually in a stable equilibrium or homeostasis, which is to say that a small change (the size of a particular population, for example) will be corrected by some negative feedback that will bring the parameter back to its original "point of balance" with the rest of the system.
In 1967, Roderick Nash published Wilderness and the American Mind, a work that has become a classic text of early environmental history.In an address to the Organization of American Historians in 1969 (published in 1970) Nash used the expression "environmental history", [4] although 1972 is generally taken as the date when the term was first coined. [5]