An impossibility theorem is a theorem that demonstrates a problem or general set of problems cannot be solved; such results are also known as proofs of impossibility, negative proofs or negative results. The cited article says they often resolve decades or centuries of work spent looking for a solution by proving there is no solution, that proving something is impossible is usually much harder than the opposite task because a proof must work in general rather than for one example, and that they are usually expressible as negative existential or universal propositions in logic. The irrationality of the square root of 2 is named as one of the oldest such proofs. Theorems that rule out a construction or solution are grouped under this concept.
Connections
In Branch
Source Impossibility Theorem
Statement Form Of
Source Vaught Conjecture (Wikipedia)
Sources
Impossibility Theorem
Wikipedia, lead section
In mathematics, an impossibility theorem is a theorem that demonstrates a problem or general set of problems cannot be solved.
In Branch: Logic and Foundations, Lead section
In mathematics, an impossibility theorem is a theorem that demonstrates a problem or general set of problems cannot be solved. These are also known as proofs of impossibility
View the SourceVaught Conjecture (Wikipedia)
Statement Form Of: Vaught's Theorem, Section: Vaught's theoremQuote, Statement Form Of: Vaught's Theorem, Section: Vaught's theorem
Vaught proved that the number of countable models of a complete theory cannot be 2.
View the Source Reader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.