|Decidability: a question, for example, whether a property applies to an object or not, is decidable if a result can be achieved within a finite time. For this decision process, an algorithm is chosen as a basis. See also halting problem, algorithms, procedures, decision theory.|
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|Berka I 543ff
Undecidability/Gödel/Tarski: an undecidable statement is decidable in an enriched metascience ((s) metalanguage?).
E.g. I 543f -
Definability/Tarski: for every deductive science, which includes arithmetic,we can specify arithmetical terms that are not definable in it - I 545 - but with methods that are used here in analogy, you can show that these terms can be defined on the basis of the considered science when enriched by variables of a higher order.
Logic, Semantics, Metamathematics: Papers from 1923-38 Indianapolis 1983
K. Berka/L. Kreiser
Logik Texte Berlin 1983