Program Synthesis and Linear Operator Semantics

For deterministic and probabilistic programs we investigate the problem of program synthesis and program optimisation (with respect to non-functional properties) in the general setting of global optimisation. This approach is based on the representation of the semantics of programs and program fragments in terms of linear operators, i.e. as matrices. We exploit in particular the fact that we can automatically generate the representation of the semantics of elementary blocks. These can then can be used in order to compositionally assemble the semantics of a whole program, i.e. the generator of the corresponding Discrete Time Markov Chain (DTMC). We also utilise a generalised version of Abstract Interpretation suitable for this linear algebraic or functional analytical framework in order to formulate semantical constraints (invariants) and optimisation objectives (for example performance requirements).Comment: In Proceedings SYNT 2014, arXiv:1407.493

Wavelets and Lattice Field Theory

When continuous fields are expanded in a wavelet basis, a D-dimensional continuum action becomes a (D+1)-dimensional lattice action on the naively discretized Poincare-patch coordinates of an Euclidean AdS(D+1). New possible criteria for acceptable actions open up.Comment: 7 pages. Contribution to Lattice2017, 18-24 June, Granada, Spai

e-Learning Nudism: Stripping Context from Content

Educational economics plays an increasing role in university development. In order to attract students well developed curricula are needed and they are expected to contain a fair amount of digital resources, which are much more expensive to create than sheets of paper in the old days. The flip side is: they can be sold. Whereas hand-outs remained an obscure asset, suitably organized electronic courseware promises to become a major business. As "Learning Management Systems" offer comprehensive services to entire universities at substantial costs, university administrators try to channel traditional teaching into new formats, hoping to serve more students at lesser expense. One catchword, capturing those concerns, is "learning object". A learning object is the equivalent of a chunk of beef, registered according to some classificatory scheme, marked by a stamp of approval by some authority, deep-frozen and waiting for delivery. Here is a more respectable description. Learning objects are digital entities designed to be used (and re-used) in learning activities.[1] They are supposed to be independent of specific educational settings, disengaged from more comprehensive courses. Information pertaining to their educational, technical and legal status is to be captured by meta-data accompanying the objects. Learning object repositories (LORs) collect those molecular units and offer facilities for search and peer evaluation

The Protestant Revolution or Wider die falsche Gelassenheit

This contribution was prompted by events in East Germany that ultimately led to German unification. Many forces contributed to the collapse of the GDR as a separate state, the final and most visible was the mass exodus via Hungary and Czechoslovakia. The Communist regime resisted change when change was taking place in most of East Germanys neighbors to the east and southeast. But an ever increasing number of increasingly restless citizens insisted on it and, not given a chance to change matters by improving the system, effected the most radical change of all: they swept away an unresponsive, cynical and calcified government

An ode to joy : a season of grief

Beethoven's Ninth in Bailey Hall the other evening, April 20, ending in an instant standing ovation by a clearly enchanted audience, was an unforgettable experience. And, like all such truly extraordinary events that are marked not only by artistic merit, but draw their power from the circumstances surrounding their creation or performance, it recalled others and enhanced their significance. I was reminded of a stellar performance on Christmas Day of 1989, only weeks after the unexpected fall of the Berlin Wall on November 9, that haunting date in German history. Few people believed it would ever happen. But now, suddenly, reunification in justice and freedom, as the truncated old national anthem phrases it, was within reach