In metadata, property equivalence is the statement that two properties have the same property extension or values. This usually (but not always) implies that the two properties have the same semantics or meaning.

In mathematics, a weak equivalence is a notion from homotopy theory that in some sense identifies objects that have the same "shape". This notion is formalized in the axiomatic definition of a model category.

The Ricardian equivalence proposition (also known as the Ricardo–de Viti–Barro equivalence theorem) is an economic hypothesis holding that consumers are forward-looking and so internalize the government's budget constraint when making their consumption decisions. This leads to the result that, for a given pattern of government spending, the method of financing such spending does not affect agents' consumption decisions, and thus, it does not change aggregate demand.