Oh, do not ask, “What is it?“
Let us go and make our visit.

On Tuesday evening, the schedule says “Prof. Yau present his new research result,” which presumably will be about the proof of the Poincare conjecture.

Would it have been worth while,
To have bitten off the matter
   with a smile,
To have squeezed the universe
   into a ball
To roll it toward some
   overwhelming question….

Yau rated the conjecture as one of  the major mathematical puzzles of the 20th Century. 
    “The conjecture is that if in a closed  three-dimensional space, any closed  curves can shrink to a point continuously, this space can be deformed to a sphere,” he said.