Hamiltonian variations [04GF]
Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.
Complete original source context · Original author HTML
Hamiltonian variations
If the Lagrangian angle of the minimizer satisfies , then we have a more elliptic argument. Given any compactly supported global Hamiltonian function on , we can associate a 1-parameter family of symplectomorphisms by exponentiating the Hamiltonian vector field. Since only moves the tangent planes by for small , the Lagrangian angle of is still within , namely the quantitatively almost calibrated condition is preserved.
Under global Hamiltonian deformations, the first variation of the Solomon functional is
We need another ingredient which is expected to hold once the Floer theory is sufficiently developed in the weak regularity setting:
- •
The class of unobstructed exact Lagrangian objects is preserved by Hamiltonian isotopies. As such should remain inside the class .
These would imply that the minimizer satisfies
for any compactly supported function on . This means as currents, which is equivalent to under the almost calibrated setting.
Remark 5.29.
The assumption that for the minimizer is not innocent, but represents a principal gap in our program to find special Lagrangian currents. The problem is that if on the minimizer , and a priori has no regularity assumption (eg. the Lagrangian angle may a priori be highly oscillatory), then we lack techniques to construct Lagrangian competitors which remain quantitatively almost calibrated.