Direct Connection between the $\text{R}_{\text{II}}$ Chain and the Nonautonomous Discrete Modified KdV Lattice

The spectral transformation technique for symmetric $\text{R}_{\text{II}}$ polynomials is developed. Use of this technique reveals that the nonautonomous discrete modified KdV (nd-mKdV) lattice is directly connected with the $\text{R}_{\text{II}}$ chain. Hankel determinant solutions to the semi-infinite nd-mKdV lattice are also presented.