[jwarden]

The authors of the QF paper describe it as "an extension of the logic of quadratic voting." They involve similar formulas and both are theoretically optimal (or efficient), and have a single equilibrium. These properties are proven using somewhat similar math.

But they apply to quite different settings and are not really the same thing. With Quadratic Voting, people pay for votes (with cost determined by a certain formula). With Quadratic Funding, people contribute to projects (with matching funds determined by a certain formula).

QV also makes many assumptions that rarely hold in reality, just like QF does. I may write an article about this someday.