Effective Polish space
Encyclopedia
In mathematical logic
, an effective Polish space is a complete separable metric space
that has a computable presentation. Such spaces are studied in effective descriptive set theory
and in constructive analysis.
computable (Moschovakis 2009:142):
Mathematical logic
Mathematical logic is a subfield of mathematics with close connections to foundations of mathematics, theoretical computer science and philosophical logic. The field includes both the mathematical study of logic and the applications of formal logic to other areas of mathematics...
, an effective Polish space is a complete separable metric space
Metric space
In mathematics, a metric space is a set where a notion of distance between elements of the set is defined.The metric space which most closely corresponds to our intuitive understanding of space is the 3-dimensional Euclidean space...
that has a computable presentation. Such spaces are studied in effective descriptive set theory
Effective descriptive set theory
Effective descriptive set theory is the branch of descriptive set theory dealing with sets of reals having lightface definitions; that is, definitions that do not require an arbitrary real parameter. Thus effective descriptive set theory combines descriptive set theory with recursion theory....
and in constructive analysis.
Definition
An effective Polish space is a complete separable metric space X with metric d such that there is a countable dense set C = (c0, c1,...) that makes the following two relations on computable (Moschovakis 2009:142):