Learnability with PAC Semantics for Multi-agent Beliefs

The tension between deduction and induction is perhaps the most fundamental issue in areas such as philosophy, cognition and artificial intelligence. In an influential paper, Valiant recognised that the challenge of learning should be integrated with deduction. In particular, he proposed a semantics to capture the quality possessed by the output of Probably Approximately Correct (PAC) learning algorithms when formulated in a logic. Although weaker than classical entailment, it allows for a powerful model-theoretic framework for answering queries. In this paper, we provide a new technical foundation to demonstrate PAC learning with multi-agent epistemic logics. To circumvent the negative results in the literature on the difficulty of robust learning with the PAC semantics, we consider so-called implicit learning where we are able to incorporate observations to the background theory in service of deciding the entailment of an epistemic query. We prove correctness of the learning procedure and discuss results on the sample complexity, that is how many observations we will need to provably assert that the query is entailed given a user-specified error bound. Finally, we investigate under what circumstances this algorithm can be made efficient. On the last point, given that reasoning in epistemic logics especially in multi-agent epistemic logics is PSPACE-complete, it might seem like there is no hope for this problem. We leverage some recent results on the so-called Representation Theorem explored for single-agent and multi-agent epistemic logics with the only knowing operator to reduce modal reasoning to propositional reasoning

Observaţii privind structura, dinamica şi abundenţa speciilor de Carabide (ord. Coleoptera, fam. Carabidae) din plantaţiile pomicole de măr

Thepaper presents the obtained results from the observations made in a apple fruit tree orchards within SC Loturi Service SRL Delesti, Vaslui County.The material collection was done using the Barber traps once a week during June -September.Several collections of entomological material captured in the soil traps were made, then the carabid species were selected and identified.The collected species belong mainly to the following genres: Harpalus, Pterostichus, Amara, Calathus, Carabus etc

Observaţii asupra entomofaunei din culturile de grâu colectată la capcanele de sol

The increase grain production is possible through the application of technology that involves the use of varieties with high yield, soil fertilization to provision according to their requirements, full mechanization of work and measures to prevent and combat specific pests and weeds. Regarding pests of grain crops grasses, they can cause annual havoc 13.8% compared to 11.6% produced by pathogens and weeds due to 9.5%. This paper presents the research on the epigenous entomofauna of wheat crops in 2016, in Focsani area used the traps type Barber and collecting biological material was conducted from May to July. The collection of the biological material was performed periodically on the following dates: 23.05; 07.06; 23.06; 07.07 using 18 traps belonging to the three experimental variants: •Variant 1 - wheat after sunflower; • Variant 2 - wheat after wheat; • Variant 3 - wheat after rape.The most commonly species found in this period are following the order: Coleoptera, Hymenoptera, Orthoptera, Heteroptera, Diptera, Colembolla etc. They were collected in addition to insects, and species belonging to the Crustacea class with the Isopods order, and the Arachnida class with the Araneae order

Observaţii cu privire la fauna epigee din culturile de grâu în condiţiile anului 2017

The observations were made in 2017, in a wheat crop located in the eastern area of Romania, in the county of Vaslui. The material was harvested using the soil traps type Barberand entomological mesh, during which several harvests of the material were made at intervals of 8 to 15 days. From the collected biological material, were retained all the species belonging to the epigee fauna, which were then determined by means of the determiners (Reitter, Panin, etc.). Following the records was established the specific structure from wheat crop, their dynamics and their abundance.The most frequently collected species were: Heteroptera, Hymenoptera, Diptera, Aracnidae, Orthoptera, and of course those belonging to the order of Coleoptera (Pseudophonus rufipes Mull., Dermestes laniarius Illig., Harpalus aeneus F., Harpalus distinendus Duft., Ophonus azureus F., Opatrum sabulosum L., Otiorrhynchus raucus F., Carabus violaceus L., Pseudophonus rufipes, Harpalus aeneus F.şi Amara crenata Payk) etc

Cercetari privind fauna de coleoptere epigee din unele culturi de grau

The study of beetles (Coleoptera) appears as a necessary scientific and practical taking into account, in particular its frequency on the meridian of the Earth, the number of species that they comprise (250,000), the largest of the class Insecta, which groups more than one million species and the many species that cause damage to global agriculture.The material was collected using Barber soil traps, from a wheat culture for consumption in the town of Delesti, Vaslui County.The observations were made in 2017, the material was collected from May to October. The material was harvested at intervals between 8 and 17 days, with a total of 5 harvests.The species most frequently collected were Opatrum sabulosum L., Otiorrhynchus raucus F., cupreus Carabus L., Pseudophonus rufipes, Harpalus aeneus Amara aenea F.şi Payk