Realizing public announcements by justifications

Modal public announcement logics study how beliefs change after public announcements. However, these logics cannot express the reason for a new belief. Justification logics fill this gap since they can formally represent evidence and justifications for an agent's belief. We present OPAL(K) and JPAL(K) , two alternative justification counterparts of Gerbrandy–Groeneveld's public announcement logic PAL(K) . We show that PAL(K) is the forgetful projection of both OPAL(K) and JPAL(K) . We also establish that JPAL(K) partially realizes PAL(K) . The question whether a similar result holds for OPAL(K) is still open.

Lower complexity bounds in justification logic

Justification Logic studies epistemic and provability phenomena by introducing justifications/proofs into the language in the form of justification terms. Pure justification logics serve as counterparts of traditional modal epistemic logics, and hybrid logics combine epistemic modalities with justification terms. The computational complexity of pure justification logics is typically lower than that of the corresponding modal logics. Moreover, the so-called reflected fragments, which still contain complete information about the respective justification logics, are known to be in~NP for a wide range of justification logics, pure and hybrid alike. This paper shows that, under reasonable additional restrictions, these reflected fragments are NP-complete, thereby proving a matching lower bound. The proof method is then extended to provide a uniform proof that the corresponding full pure justification logics are $\Pi^p_2$-hard, reproving and generalizing an earlier result by Milnikel.

Decidability for some justification logics with negative introspection

Justification logics are modal logics that include justifications for the agent's knowledge. So far, there are no decidability results available for justification logics with negative introspection. In this paper, we develop a novel model construction for such logics and show that justification logics with negative introspection are decidable for finite constant specifications.

First steps towards probabilistic justification logic

In this article, we introduce the probabilistic justification logic PJ, a logic in which we can reason about the probability of justification statements. We present its syntax and semantics, and establish a strong completeness theorem. Moreover, we investigate the relationship between PJ and the logic of uncertain justifications.

Can stable isotope analysis and tooth histology assist in detecting stillbirth? An approach using neonatal remains from the Roman settlement Studen Petinesca

Infant burials in Roman settlements are a common observation. Even though ancient authors provide information many questions remain uncertain. For instance, the burial ritual for stillbirth and infanticide neonates is not specifically mentioned. This study therefore aimed to investigate the application of stable nitrogen (δ15N) and carbon (δ13C) isotopes from neonatal bone collagen in differentiating between a breastfeeding signal and stillbirth or a short survival of less than ten days. For this purpose collagen of 11 human and 14 non-human bones from the Roman settlement Petinesca (1st - 3rd century AD, Switzerland) was extracted and analysed for δ15N and δ13C. Tooth histology was performed for the central incisor and canine of the right mandible in order to investigate the presence of a neonatal line. According to the length of the long bones the age varied between 8.5 lunar months to 2 months ex utero. The stable isotope results provided a breastfeeding signal for all except one individual where the breastfeeding signal was absent. The tooth histological analysis of this individual exhibited no neonatal line. It is concluded that stable isotope analysis could indicate stillbirth or a short survival after birth. The tooth histology confirmed the stable isotope results. Furthermore, this might indicate that the burial ritual did not differentiate between stillbirth and neonates, who died within the time span stated by ancient authors of up to 40 days of age or the appearance of teeth. However, for further justifications additional research is going to be conducted.

Justification of Data Warehousing Projects

Project justification is regarded as one of the major methodological deficits in Data Warehousing practice. As reasons for applying inappropriate methods, performing incomplete evaluations, or even entirely omitting justifications, the special nature of Data Warehousing benefits and the large portion of infrastructure-related activities are stated. In this paper, the economic justification of Data Warehousing projects is analyzed, and first results from a large academiaindustry collaboration project in the field of non-technical issues of Data Warehousing are presented. As conceptual foundations, the role of the Data Warehouse system in corporate application architectures is analyzed, and the specific properties of Data Warehousing projects are discussed. Based on an applicability analysis of traditional approaches to economic IT project justification, basic steps and responsibilities for the justification of Data Warehousing projects are derived.

Probabilistic Justification Logic

We present a probabilistic justification logic, PPJ, to study rational belief, degrees of belief and justifications. We establish soundness and completeness for PPJ and show that its satisfiability problem is decidable. In the last part we use PPJ to provide a solution to the lottery paradox.