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LtU ForumSome New Directions for ACP ResearchThis paper at ArXiv.org lists some new directions for research related to the Algebra of Communicating Processes (ACP). Most of these directions have been inspired by work on SubScript, an ACP based extension to the programming language Scala. SubScript applies several new ideas that build on ACP, but currently these lack formal treatment. Some of these new ideas are rather fundamental. E.g. it appears that the theory of ACP may well apply to structures of any kind of items, rather than to just processes. The aim of this list is to raise awareness of the research community about these new ideas; this could help both the research area and the programming language SubScript. Practical Principled FRP: Forget the past, change the future, FRPNow!A new ICFP 15 paper by Ploeg and Claessen; abstract:
Who can make LtU2?If we had voting on things (a la reddit, slashdot, hacker news, etc.) I think we'd all be better off. There are technological things which won't outright fix everything, but should greatly help I should think. But we'd need somebody who can actually set that stuff up. Bisimulation in security auditingBisimulation has been an important topic in Computer Science (e.g. intensely studied for process calculi) which may be applicable to an important emerging issue for computer engineering, namely security auditing. See bottom of page 3 of Distributed Public Recording: Providing Security Without the Risks of Mandatory Backdoors The PageFault Weird Machine: Lessons in Instructionless ComputationIn case one instruction is one too many for you. A compiler which executes instructionless code through triggering pagefaults.
Dedekind, Cantor, Conway, & Hewitt (w/ some Chomsky)Here, I will attempt to cool down controversy on LtU over Hewitt's construction of Real by explaining it in more familiar terms. I think this will help to shed some light on Direct Logic and begin to hint why it is interesting in a PLT context. I will borrow conceptually from John H. Conway who wrote, in "On numbers and games":
Hewitt can be read as constructing Real by specifying a set of 3way partitions of the dyadic fractions between 0 and 1. Every Real in [0..1] corresponds to three sets: {L  M  R} The sets are ordered so that no member of L is greater than or equal to any member of M or R, no member of M is greater than or equal to any member of R. Zero: 0 ≡ {{}  {}  Dyad} where Dyad is the set of all dyadic fractions between 0 and 1 One: 1 ≡ {Dyad  {}  {}} Hopefully the dyadic fractions are themselves members of Real and we can memorialize that fact in a manner similar to Dedekind: ∀d ∈ Dyad, {d_{l}  { d }  d_{r} } ∈ ℝ where d_{l} ≡ { x ∈ Dyad  x < d } and d_{r} ≡ { x ∈ Dyad  x > d } Note: the Real {d_{l}  { d }  d_{r} } is called d. The rationals in general correspond to regular languages as follows: Let Rat be the set of of sets of finite strings of 0 and 1 such that: ∀r in Rat, r is a regular language r is well ordered by a prefix relation ∀s in r, s is finite length and ends with 1 r_{l} ≡ { d ∈ Dyad  ∃x ∈ r, x > d } r_{m} ≡ { d ∈ r  ∀x ∈ r, x <= d } r_{r} ≡ { d ∈ Dyad  ∃x ∈ r, x < d } Note: the Real { r_{l}, r_{m}, r_{r} } is called r } As you can see, the subset of Real given by Rat is the set of all rational fractions between 0 and 1. The rationals are given by certain regular languages over the alphabet {0,1}. Similarly, the constructible reals are given by certain recursivvely enumerable languages. Let Tructable be the set of all recursively enumerable sets of finite strings of 0s and 1s, each string ending with a 1, such that each member of Tructable is well ordered by a prefix relation. By analogous construction to the rationals: ∀ t ∈ Tructable, { t_{l}, t_{m}, t_{r} } is in Real All rationals (dyadic and otherwise) are Tructable. Finally, we consider a set of languages of finite strings for which the generator functions are nondeterministic. Let Fracs be the set of all sets of finite strings of 0s and 1s, each string ending with a 1, such that each member of Fracs is well ordered by a prefix relation. By analogous construction, ∀ f ∈ Fracs, { f_{l}, f_{m}, f_{r} } is in Real Note that if a member f of Fracs has a maximal element, then f is also a dyadic rational. Note that if a member f is a regular language over {0,1}, then it is a rational. Note that if a member of f is a recursively enumerable set, then it is a tructable real. There are other possibilities. By a diagonalization argument, we know that Fracs contains members f which are not recursively enumerable. Those f are the unconstructible reals. Let's suppose that the real world contains fair randomness. For example, there is a coin flip or some other kind of measurement we can repeat that will produce random outcomes. Neither heads or tails will be permanently starved. A sequence of coinflips on a given worldline will eventually produce both a 0 and a 1. Furthermore, on some worldlines, the sequence of coin flips is not described by any recursively enumerable function (at least assuming that there is no upper bound on the number of times we get to flip the coin). The number of possible worldlines on which coin flips might be recorded is uncountable and, indeed, corresponds nicely to the members of Fracs. In other words, a machine can enumerate the members of any f in Fracs, from shortest to longest. Such a machine, on a particular worldline, is pretty much what Hewitt means by an "Actor address". SPLASH 2015  2nd Combined Call for Contributions/************************************************************************************/ Pittsburgh, Pennsylvania, USA Sponsored by ACM SIGPLAN /************************************************************************************/ CoLocated Conferences: SLE, GPCE, DBPL, PLoP The ACM SIGPLAN conference on Systems, Programming, Languages and Applications: Software for Humanity (SPLASH) embraces all aspects of software construction and delivery to make it the premier conference at the intersection of programming, languages, and software engineering. SPLASH is now accepting submissions. We invite high quality submissions describing original and unpublished work. Most of the following tracks have submissions due: 30 JUNE ** Demos ** Submissions Due: 30 June, 2015 ** Doctoral Symposium ** Submissions Due: 30 June, 2015 ** Dynamic Languages Symposium (DLS) ** Submissions Due: 15 June, 2015 ** OOPSLA Artifacts ** Submissions Due: 9 June, 2015 ** Posters ** Submissions Due: 30 June, 2015 ** SPLASHE ** Submissions Due: 30 June, 2015 ** Student Research Competition ** Submissions Due: 30 June, 2015 ** Student Volunteers ** Submissions Due: 7 August, 2015 ** Tutorials ** Submissions Due: 30 June, 2015 ** Wavefront ** Submissions Due: 30 June, 2015 ** Workshops ** Late Phase Submissions Due: 30 June, 2015 ** CoLocated Events ** SLE  8th International Conference on Software Language Engineering (SLE) GPCE  14th International Conference on Generative Programming: Concepts & Experiences (GPCE) DBPL  15th Symposium on Database Programming Languages (DBPL) PLoP  22nd International Conference on Pattern Languages of Programming (PLoP) Information: Location: Organization: By craiganslow at 20150621 16:20  LtU Forum  login or register to post comments  other blogs  298 reads
The single instruction compilerThe M/o/Vfuscator (short 'o', sounds like "mobfuscator") compiles programs into "mov" instructions, and only "mov" instructions. Arithmetic, comparisons, jumps, function calls, and everything else a program needs are all emulated through movs, and there is no SMC cheating. The compiler is inspired by the paper "mov is Turingcomplete", by Stephen Dolan. The original M/o/Vfuscator (M/o/Vfuscator 1.0) compiles programs from the esoteric language BrainF@$!, and is best used in conjunction with the BFBASIC compiler by Jeffry Johnston. M/o/Vfuscator 2.0 is a complete C compiler, and will be available soon. By marco at 20150621 12:11  LtU Forum  login or register to post comments  other blogs  606 reads
Strengthening Process CalculiMingsheng Ying: Topology in process calculus: approximate correctness and infinite evolution of concurrent programs. Since process calculi come up now and then, I borrowed this book from the library and tried to read it. Cannot claim to have grokked it, but I was excited reading through the example applications toward the end of it. I (think I) am hoping this kind of work can find its way into the mainstream somehow, some day.

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