Using firm-level data for Jordan, the paper estimates the extent to which growth spillovers from foreign direct investment (FDI) to local firms stem from persistent learning externalities (i.e., they endure even after foreign investment leaves as knowledge has been transferred to local firms) or...

We consider corner transfer matrices for the regular Ising model and show that finding a diagonal representation is a soluble problem in interacting fermions. We show how the requirement of having an invertible diagonalising transformation determines which representation must be used and explain...

We consider the quantum non-linear Schrödinger equation as a quantum field model in 1 + 1 space-time. It has been recently solved by the quantum inverse method and by the method of intertwining operators. Expressions obtained by the two methods are formally different. We show here that...

We construct explicit forms for two non-trivial conservation laws of the quantum non-linear Schrödinger equation and show that they have the correct quasi-classical limit. For H4 the second quantised form cannot be obtained by normal ordering of the classical conserved quantity H4cl. We show...