2 problems

Let $\beta$ be a positive braid, let $L_\beta$ be its braid-positive link closure, and let the corresponding Legendrian closure be represented by the front diagram $f_\beta$. A Leg…

Let $\mathcal{X}$ be a globally hyperbolic spacetime whose Cauchy surface is not homeomorphic to the sphere. Let $x,y\in\mathcal{X}$ be causally related points, and consider future…