We demonstrate experimentally and explain theoretically polarization-preserving imaging through a lossy amplitude-distorting medium. This is accomplished by propagating the beam, before its arrival at the lossy distorting medium, through a (multi) mode- and polarization-scrambling fiber and reflecting the signal, after it has passed the lossy distorting medium, from a photorefractive phase-conj...

Improving the availability of information technology and increasing volume digital traffic leads to an important problem data protection. A particularly pressing issue is transmitting confidential through unsecured communication channels, such as Internet. Recently, there has been a significant increase in number cyberattacks, including attempts intercept steal transmitted global networks. Info...

by Sean Walsh The subject of this dissertation is arithmetical knowledge and arithmetical definability. The first two chapters contain respectively a critique of a logicist account of a preferred means by which we may legitimately infer to arithmetical truths and a tentative defense of an empiricist account. According to the logicist account, one may infer from quasi-logical truths to patently ...

D uring sperm production in mammals, the process of meiosis generates sper-matozoa that are genetically different but functionally equivalent. So, with respect to the sex chromosomes, for example, equal numbers of sperm are produced carrying either an X or a Y chromosome. Because X and Y sperm are equally capable of fertilizing an egg, equal numbers of male and female embryos are produced, and ...

Any regular mixed Tsirelson space T (θn, Sn)IN for which θn θn → 0, where θ = limn θ n , is shown to be arbitrarily distortable. Certain asymptotic `1 constants for those and other mixed Tsirelson spaces are calculated. Also a combinatorial result on the Schreier families (Sα)α<ω1 is proved and an application is given to show that for every Banach space X with a basis (ei), the two ∆-spectrums ...

Fitch’s paradox shows, from fairly innocent-looking assumptions, that if there are any unknown truths, then there are unknowable truths. This is generally thought to deliver a blow to antirealist positions that imply that all truths are knowable. The present paper argues that a probabilistic version of antirealism escapes Fitch’s result while still offering all that antirealists should care for...

A simple replacement approach is used to construct new symmetric and affine designs from projective or affine spaces. This is used to construct symmetric designs with a given automorphism group, to study GMW-designs, and to construct new affine designs whose automorphism group fixes a point and has just two pointand block-orbits.