..E
 effective

 effective procedure
 An effective procedure is an unambiguous prescription for computing some function or solving a class of problems.
 effectively computable
 A function is effectively computable if there is an effective procedure for computing the value of the function.
 effectively decidable
 A class of problems, or a set, is effectively decidable if there exists an effective procedure which will determine the answer to the problem (or membership of the set) terminating with the correct answer within a finite number of steps, for all candidates.
 effectively semidecidable
 A class of problems, or a set, is effectively semidecidable if there exists an effective procedure which terminates with a positive answer whenever the answer to the problem or the membership question is positive, but which may fail to terminate in the case that the answer is negative.

empirical
 based on observation or experiment

empiricist
 one who emphasises the role of sensory experience or experimental evidence in the justification of knowledge.

epistemology
 The theory of knowledge.
 epistemic logic
 A logic for reasoning about knowledge and belief.

extension

 of a set
 the membership of the set
 of a property
 the collection of things which have the property
 of a function
 the mapping defined by the function, as distinct from any algorithm, rule or formula used to define the function

extensional

 of a set theory
 A set theory is extensional when two sets are equal iff they have the same extension.
 of a higherorder logic
 A higher order logic is extensional when two properties or functions are equal iff they have the same extension.
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created 1994922 modified 20021012