Floer's first pivotal contribution was a solution of a special case of Arnold's conjecture on fixed points of a symplectomorphism.

Because of his work on Arnold's conjecture and his development of instanton homology, he achieved wide recognition and was invited as a plenary speaker for the International Congress of Mathematicians held in Kyoto in August 1990.

[2] "Andreas Floer's life was tragically interrupted, but his mathematical visions and striking contributions have provided powerful methods which are being applied to problems which seemed to be intractable only a few years ago.

"[1] Simon Donaldson wrote: "The concept of Floer homology is one of the most striking developments in differential geometry over the past 20 years.

The development of new Floer theoretic tools continues at a remarkable pace and underlies many of the recent breakthroughs in these diverse fields.