  In this paper we prove the isomorphism of the positive half of the quantum
toroidal algebra and the positive half of the Maulik-Okounkov quantum affine
algebra of affine type $A$ via the monodromy representation for the Dubrovin
connection. The main tool is on the proof of the fact that the degeneration
limit of the algebraic quantum difference equation is the same as that of the
Okounkov-Smirnov geometric quantum difference equation.
