Adjective
non-constructive (not comparable)
Alternative form of nonconstructive.
Alan Turing considers: "non-constructive systems of logic with which not all the steps in a proof are mechanical, some being intuitive". Source: Internet
The uniform boundedness principle yields a simple non-constructive proof of this fact. Source: Internet
In addition, some adherents of these schools reject non-constructive proofs, such as a proof by contradiction. Source: Internet
This is something undeniably abstract, and non-constructive, but also powerful in its own way. Source: Internet
This set is called 'true reachable propositions' because in non-constructive approaches to the foundations of mathematics, the set of true propositions may be larger than the set recursively constructed from the axioms and rules of inference. Source: Internet