Maslov cycle
= Maslov cycle
{c}
Relative to a fixed <Lagrangian subspace> $L_0$, the Maslov cycle consists of Lagrangian subspaces $L$ with $L\cap L_0\ne0$. In a two-dimensional symplectic space all lines are Lagrangian, and the cycle is the single line $L_0$ in the projective line. Fibrewise versions yield sections of a projective-line bundle and record passage through a prescribed vertical direction.