We consider structural completeness in modal logics. The main result is the necessary and sufficient condition for modal logics over K4 to be hereditarily structurally complete: a modal logic λ is hereditarily structurally complete $\operatorname{iff} \lambda$ is not included in any logic from the list of twenty special tabular logics. Hence there are exactly twenty maximal structurally incomplete modal logics above K4 and they are all tabular.

LetEO be the elementary ontology of Leniewski formalized as in Iwanu [1], and letLS be the monadic second-order calculus of predicates. In this paper we give an example of a recursive function , defined on the formulas of the language ofEO with values in the set of formulas of the language of LS, such that EO A iff LS (A) for each formulaA.

The recent exchange on the quantum justification of the Periodic System of the Elements in this Journal between Scerri [Foundations of Chemistry 6: 93–116, 2004] and Friedrich [Foundations of Chemistry 6: 117–132, 2004] is supplemented by some methodological comments.

In this paper we present an executable approach to model interactions between agents that involve sensitive, privacy-related information. The approach is formal and based on deontic, epistemic and action logic. It is conceptually related to the Belief-Desire-Intention model of Bratman. Our approach uses the concept of sphere as developed by Waltzer to capture the notion that information is provided mostly with restrictions regarding its application. We use software agent technology to create an executable approach. Our agents hold beliefs about the (...) world, have goals and commitment to the goals. They have the capacity to reason about different courses of action, and communicate with one another. The main new ingredient of our approach is the idea to model information itself as an intentional agent whose main goal it is to preserve the integrity of the information and regulate its dissemination. We demonstrate our approach by applying it to an important process in the insurance industry: applying for a life insurance. In this paper we will: (1) describe the challenge organizational complexity poses in moral reasoning about informational relationships; (2) propose an executable approach, using software agents with reasoning capacities grounded in modal logic, in which moral constraints on informational relatio nships can be modeled and investigated; (3) describe the details of our approach, in which information itself is modeled as an intentional agent in its own right; (4) test and validate it by applying it to a concrete ‘hard case’ from the insurance industry; and (5) conclude that our approach upholds and offers potential for both research and practical application. (shrink)

We study quasi-characterizing inference rules (this notion was introduced into consideration by A. Citkin (1977). The main result of our paper is a complete description of all self-admissible quasi-characterizing inference rules. It is shown that a quasi-characterizing rule is self-admissible iff the frame of the algebra generating this rule is not rigid. We also prove that self-admissible rules are always admissible in canonical, in a sense, logics S4 or IPC regarding the type of algebra generating rules.

We prove that the first order theory of the fixed point algebra corresponding to an r.e. consistent theory containing arithmetic is hereditarily undecidable.

Lead shot deposited in fields and woodlands near shooting rangesand intense, upland, hunting adds an enormous tonnage of lead toenvironments, worldwide. This contamination is not remedied bybanning lead shot use only for waterfowl hunting. Lead pelletsdisintegrate extremely slowly, during which time they may beingested from the soil by wild birds, livestock, or silage-makingmachinery, and cause sublethal or fatal lead poisoning. Leadpellet corrosion products contaminate soil, surface waters, andground waters, often exceeding permissible levels. Plants do notconcentrate much lead from the soil, (...) except when grown in acidicsoils of heavily-contaminated shooting ranges. Inheavily-contaminated sites, earthworms ingest leadcompounds which are bioaccumulated in higher consumersof food webs. Non-toxic substitutes made from steelor bismuth are available internationally and areeffective for all types of hunting and targetshooting. Many nations are slow to require their use,despite the marked awareness of the problems of leadshot contamination and toxicosis. This is due tohunters and international sport shooting organizationsopposing the use of non-toxic substitutes and overtemphasis by government agencies on the burden ofscientific proof for every situation, rather thantaking preventative action according to thePrecautionary Principle. The ethical approach ofDenmark and The Netherlands, which banned all uses oflead shot, is advocated as a precedent for othernations to adopt. (shrink)

Of course you know the movie, just by cultural assimilation if not by having seen it. There’s this young elephant, Dumbo, who has laughably big ears and has been pitiably separated from his mom. He’s aided by a friendly talking mouse[ii] into translating those otherwise hapless ears into the power of flight, which he eventually uses to rescue his mom and live happily ever after. The way the wily mouse gets Dumbo to believe that he could fly is to give (...) him a “magic feather” which, held in his trunk, demonstrably imparts the gift of flight. Naturally the mouse believes throughout all this that Dumbo can fly anyway, but he also knows that Dumbo needs the feather as a confidence-builder to do so. At the critical juncture of the tale Dumbo loses the feather after being pushed off a precipice, and he thus plummets perilously towards earth—only to find at the last moment that he can indeed fly on his own. (shrink)

In recent years, the phenomena of hormonal control, embryonic determination and pattern formation have been receiving intensive scrutiny from molecular biologists. In the following «Roots» contribution, Professor Sir Vincent B. Wigglesworth reviews some of the seminal work that he did on these subjects in the insect Rhodnius prolixus.

Dieser Buchtitel ist Teil des Digitalisierungsprojekts Springer Book Archives mit Publikationen, die seit den Anfängen des Verlags von 1842 erschienen sind. Der Verlag stellt mit diesem Archiv Quellen für die historische wie auch die disziplingeschichtliche Forschung zur Verfügung, die jeweils im historischen Kontext betrachtet werden müssen. Dieser Titel erschien in der Zeit vor 1945 und wird daher in seiner zeittypischen politisch-ideologischen Ausrichtung vom Verlag nicht beworben.