KnowraEuler's four-square identityLinked fromLinked fromThe 3 pages that link to Euler's four-square identity, each with the reason it gives.All 3Broader topic 1Compared with 2Brahmagupta–Fibonacci identityCompared with: It preserves a similar product rule but uses four terms rather than two.Degen's eight-square identityCompared with: It is the lower-dimensional quaternion analogue of Degen's formula.