A multiplicative universal property for real algebraic $K$-theory

Abstract

We prove that the real $K$-theory functor is lax symmetric monoidal. Moreover, it is initial among those real functors ${\mathsf{Wald}}_{\infty }^{\mathrm{gd}}\to {\mathsf{Sp}}^{C_2}$ that are additive and lax symmetric monoidal.