The Collaborative International Dictionary
Decidable \De*cid"a*ble\, a. Capable of being decided; determinable.
Wiktionary
a. 1 capable of being decided. 2 (context computer science English) describing a set for which there exists an algorithm that will determine whether any element is or is not within the set in a finite amount of time. 3 (context logic English) in intuitionistic logic, a proposition ''P'' is decidable in a given theory if it can be proven from the theory that "either ''P'' or not ''P''", i.e. in symbols: .http://plato.stanford.edu/entries/logic-intuitionistic/
Usage examples of "decidable".
EXERCISE: Prove that every consistent decidable first-order theory has a consistent decidable complete extension.
All Michael Pemulis had done was codify basic principles and impose a sort of matrix of decidable strategy.
Even in closed axiomatic systems, not all propositions are decidable.