Physics at its best brings the world together. Its power is that a single simple framework can describe wildly different systems. But even the greatest descriptive equations reach their limits ...

The Lagrangian description of absolutely continnous curves of probability measures on the real line is analyzed. Whereas each such curve admits a Lagrangian description as a well-defined flow of its ...

When a fluid is in motion, it must move in such a way that mass is conserved. To see how mass conservation places restrictions on the velocity field, consider the steady flow of fluid through a duct ...

We show that the norm continuity of the resolvent for a Volterra equation of scalar type is equivalent to the decay to zero of a holomorphic operator family along some imaginary axis. Journal ...