### Lattice angles and quadratic forms (Lenny Fukshansky, CMC)

### Lattice angles and quadratic forms (Lenny Fukshansky, CMC)

What are the possible angles between two integer vectors in R^n? If we fix one such possible angle and one integer vector x, is there always another integer vector y that makes this angle with x? Assuming that x makes a given angle with some vector, how can we find the shortest such vector y? […]