Noun
unprovability (uncountable)
The condition of being unprovable
However, we know that the sequent calculus is complete with respect to natural deduction, so it is enough to show this unprovability in the sequent calculus. Source: Internet
Diagonalization The next step in the proof is to obtain a statement which, indirectly, asserts its own unprovability. Source: Internet
This sentence does not directly refer to itself, but when the stated transformation is made the original sentence is obtained as a result, and thus this sentence indirectly asserts its own unprovability. Source: Internet
This was done by a direct proof of the unprovability of the principle of transfinite induction, used in his 1936 proof of consistency, within Peano arithmetic. Source: Internet
Thus, showing unprovability is much easier, because there are only a finite number of cases to consider, and each case is composed entirely of sub-propositions of the conclusion. Source: Internet