Semi-infinite construction for the double Yangian of type A1(1)

We consider certain infinite dimensional modules of level 1 for the double Yangian DY(gl2) which are based on the Iohara–Kohno realization. We show that they possess topological bases of Feigin–Stoyanovsky-type, i.e. the bases expressed in terms of semi-infinite monomials of certain integrable operators which stabilize and satisfy the difference two condition. Finally, we give some applications of these bases to the representation theory of the corresponding quantum affine vertex algebra.