I come across this description of an external product between RGSW and RLWE ciphertext:
C c → c′: this procedure computes the external product between an RGSW and RLWE ciphertext. Specifically, it takes takes C = RGSWs(m1) and c = RLWEs(m2), and outputs c′ = C⊤ · G−1(c) = RLWEs(m1 · m2).
Does OpenFHE support this function?
Internally it is is done as part of bootstrapping (in AddToAcc* methods), but it is not currently exposed through the user API