Illegal migration, enforcement and minimum wage

This paper examines the connection between illegal migration, minimum wages and enforcement policy. We first explore the employers’ decision regarding the employment of illegal migrants in the presence of an effective minimum wage. We show that the employers’ decision depends on the wage gap between those of the legal and illegal workers and on the penalty for employing illegal workers. We consider the effects a change in the minimum wage has on the employment of illegal immigrants and local workers. We conclude by considering the optimal migration policy taking into consideration social welfare issues

Development of improved single crystal gallium phosphide solar cells final report, jun. 12, 1963 - aug. 12, 1964

Single crystal gallium phosphide solar cell

Note on the symmetry of perturbed Hartree-Fock and X-alpha wavefunctions

It is shown that the first order orbitals for X-alpha or Hartree-Fock atoms perturbed by multipole electric fields have the expected symmetry properties

On Colorful Bin Packing Games

We consider colorful bin packing games in which selfish players control a set of items which are to be packed into a minimum number of unit capacity bins. Each item has one of $m\geq 2$ colors and cannot be packed next to an item of the same color. All bins have the same unitary cost which is shared among the items it contains, so that players are interested in selecting a bin of minimum shared cost. We adopt two standard cost sharing functions: the egalitarian cost function which equally shares the cost of a bin among the items it contains, and the proportional cost function which shares the cost of a bin among the items it contains proportionally to their sizes. Although, under both cost functions, colorful bin packing games do not converge in general to a (pure) Nash equilibrium, we show that Nash equilibria are guaranteed to exist and we design an algorithm for computing a Nash equilibrium whose running time is polynomial under the egalitarian cost function and pseudo-polynomial for a constant number of colors under the proportional one. We also provide a complete characterization of the efficiency of Nash equilibria under both cost functions for general games, by showing that the prices of anarchy and stability are unbounded when $m\geq 3$ while they are equal to 3 for black and white games, where $m=2$. We finally focus on games with uniform sizes (i.e., all items have the same size) for which the two cost functions coincide. We show again a tight characterization of the efficiency of Nash equilibria and design an algorithm which returns Nash equilibria with best achievable performance

Recent developments in perturbation theory

Rayleigh-Schroeder perturbation theory - degenerate and non-degenerate states - quantum chemistry - other perturbation equation

Improvement of uncoupled Hartree-Fock expectation values for physical properties

Hartree-Fock calculation method as zero-order approximation for determining atomic and molecular second-order propertie

Infrared cutoffs and the adiabatic limit in noncommutative spacetime

We discuss appropriate infrared cutoffs and their adiabatic limit for field theories on the noncommutative Minkowski space in the Yang-Feldman formalism. In order to do this, we consider a mass term as interaction term. We show that an infrared cutoff can be defined quite analogously to the commutative case and that the adiabatic limit of the two-point function exists and coincides with the expectation, to all orders.Comment: 19 page

Removal of violations of the Master Ward Identity in perturbative QFT

We study the appearance of anomalies of the Master Ward Identity, which is a universal renormalization condition in perturbative QFT. The main insight of the present paper is that any violation of the Master Ward Identity can be expressed as a LOCAL interacting field; this is a version of the well-known Quantum Action Principle of Lowenstein and Lam. Proceeding in a proper field formalism by induction on the order in $\hbar$, this knowledge about the structure of possible anomalies as well as techniques of algebraic renormalization are used to remove possible anomalies by finite renormalizations. As an example the method is applied to prove the Ward identities of the O(N) scalar field model.Comment: 51 pages. v2: a few formulations improved, one reference added. v3: a few mistakes corrected and one additional reference. v4: version to be printed in Reviews in Mathematical Physic