Classical Hamiltonian Reduction On $D(2\mathrm{\mid }1;\alpha )$ Chern-Simons Gauge Theory and Large N=4 Superconformal Symmetry

3d Chern-Simons gauge theory has a strong connection with 2d CFT and link invariants in knot theory. We impose some constraints on the $D(2\mathrm{\mid }1;\alpha )$ CS theory in the similar context of the hamiltonian reduction of 2d superconformal algebras. There Hilbert states in $D(2\mathrm{\mid }1;\alpha )$ CS theory are partly identified with characters of the large N=4 SCFT by their transformation properties.