Quadratic funding (also known as quadratic finance, liberal radical mechanism, or plural funding) is a public good provision mechanism. Participants can propose public good projects and choose how much to contribute to any potential project. Contributions are matched by taking the square root of each contribution, summing them, and taking the square of the resulting sum. Mathematically, the formula is where represents individual contributions.
Further reading
Buterin, Vitalik (2019) Quadratic payments: a primer, Vitalik Buterin’s Website.
Buterin, Vitalik, Zoë Hitzig & E. Glen Weyl (2019) A Flexible Design for Funding Public Goods, Management Science 65, no. 11: 5171–87.
Freitas, Luis V M & Wilfredo L Maldonado (2022) Quadratic Funding with Incomplete Information, GPI Working Paper No. 10 − 2022.