Hyperfinite type II-infinity factor

In mathematics, the hyperfinite type II_∞ factor is a special von Neumann algebra. Its center consists only of multiples of the identity operator, so it is a factor.

While there are other factors of type II_∞, there is a unique hyperfinite one, up to isomorphism. It consists of those infinite square matrices with entries in the hyperfinite type II₁ factor that define bounded operators.