Two-parameter Littlewood identities and half-space Yang--Baxter random fields for stable spin Hall--Littlewood symmetric functions

We prove a two-parameter skew Littlewood identity for stable spin Hall--Littlewood symmetric functions, generalizing Warnaar's identity. This identity yields a half-space extension of the Yang--Baxter random field of Bufetov and Petrov. Using their stochastic Yang--Baxter move together with the skew