Justification logics are propositional modal-like logics that instead of statements A is known include statements of the form A is known for reason t where the term t can represent an informal justification for A or a formal proof of A. In our present work, we introduce model-theoretic tools, namely: filtrations and a certain form of generated submodels, in the context of justification logic in...

1. The Hilbert-Gentzen Thesis This paper is concerned with real proofs as opposed to formal proofs, and specifically with the ultimate reason of real proofs ('Why Proof?') and with the notion of real proof ('What is a Proof?'). Several people believed and still believe that real proofs can be represented by formal proofs. A recent example is provided by Macintyre who claims that " one could go ...

Family Location and Caregiving Patterns from an International Perspective This paper conducts a cross-national econometric analysis of intra-family location and caregiving patterns. First, we assess, from an international perspective, the relationship between family structure and the geographic proximity between adult children and their parents. We then examine whether differences in family str...

BACKGROUND Higher levels of frailty result in higher risks of adverse frailty outcomes such as hospitalisation and mortality. There are, however, indications that more factors than solely frailty play a role in the development of these outcomes. The presence of resources, e.g. sufficient income and good self-management abilities, might slow down the pathway from level of frailty to adverse outc...

This paper presents a model of partial observability applied to the childcare market in Britain. We simultaneously estimate the demand and use and calculate the excess demand for childcare. We find a large queue with nearly half of the mothers demanding childcare queuing for it. We also find that formal and informal care are not substitute, implying that policies increasing the supply of formal...

Mechanized proof tools have not been eagerly adopted by the potential user community. This lack of penetration is sometimes attributed to the fact that the employment of theorem provers for formal verification is often thought to be a difficult and involved task. As a consequence, many researchers are addressing the issue of usability, and are working towards straightforward and effective ways ...

Formal object-oriented software development integrates the techniques of objectorientation and formal methods and thus combines the advantages of both. This paper presents a hypertext system as a case study of formal object-oriented software development. We describe the development of a hypertext system, beginning with informal steps towards an object-oriented model and concluding with the appl...

in present paper, first the concept of informal economy and its place in the economic literature has been described. then the causes and factors involved in providing the informal sector was examined and the volume of informal economy was estimated. second, the effect of inflation on informal economy was surveyed. to estimate the volume of informal sector, residual discrepancy method was used a...

BACKGROUND Transfers of money and help with daily activities by family and friends are important sources of support for older people and contribute to their well being. On the other hand, older adults are not only recipients of support but also important providers of support and financial transfers as giving and receiving are often reciprocal. For this, it is important to understand the determi...