In theoretical physics, a no-go theorem is a theorem that states that a particular situation is not physically possible.
This type of theorem imposes boundaries on certain mathematical or physical possibilities via a proof by contradiction.
A few of them are broad, general categories under which several theorems fall.
Other names are broad and general-sounding but only refer to a single theorem.
The difference between this impossibility and that of the no-go theorems is that a proof of impossibility states a category of logical proposition that may never be true; a no-go theorem instead presents a sequence of events that may never occur.