Abstract: As part of an interdisciplinary approach, historians are increasingly using the ideas and methods of the mathematical sciences in their research. This, for example, arises in reconstruction problems from the field of historical geography, when the initial data is insufficient for traditional analysis. The subject of this study is to model the system of spatial distribution of the medieval population and demonstrate its results using a specific example. To take into account the condition of territory heterogeneity during modeling, the author develops a variational approach proposed by S.M. Huseyn-Zade. Using the methods of the calculus of variations and Pareto optimality within the framework of this approach makes it possible to identify and numerically describe the relationships between the optimal parameters of the system. To solve this problem of reconstruction, a model of a two-level hierarchy of placement of centers was previously proposed. Its approbation on the material of the scribal description of the Shelonskaya Pyatina of the Novgorod land at the end of the 15th century showed a high degree of correlation between real and theoretical data. The first surviving scribal description of the Pskov lands dates back to the second half of the 80s XVI century. It records a huge mass of abandoned lands as a result of the Livonian War. To assess the scale of this crisis, we first need data on the size of the rural population in the previous period of time. Unfortunately, the scribal description of the mid-16th century, which is closest to it in time, has not survived. However, the above-mentioned first surviving scribal description contains retrospective information about an earlier time, which makes it possible to apply the modeling results to solve the desired reconstruction problem, which is novel.

Abstract: The subject of this study is the modeling of the spatial distribution of the medieval population. To take into account the conditions of heterogeneity of the territory in modeling, the author develops a variational approach proposed by S.M. Huseyn-Zadeh. The model is based on the idea of settlement, placement of the population on the territory as a process in which each of its participants is guided in their activities by achieving goals dictated by natural considerations, for example, maximum accessibility to their cultivated area, maximum proximity to the central settlement (center). Using the methods of calculus of variations and the concept of Pareto optimality within this approach makes it possible to identify and numerically describe the relationships between the optimal parameters of the system. In the previous paper, the author proposed a model of a one-level hierarchy of the placement of centers (central settlements). Additional analysis of historical material leads to the need to refine the model, namely, adding a hierarchy of centers to it. In this regard, this paper proposes a model of spatial placement with a two-level hierarchy of centers.
The approbation of the proposed model is carried out on the material of the scribal books of the Shelonskaya Pyatina of the Novgorod land of the end of the XV century. The high degree of conformity of the obtained theoretical and empirical data allows us to consider mathematical modeling as an adequate and convenient auxiliary tool in studying the nature and dynamics of historical rural settlement systems.
The possibilities of the proposed modeling also in terms of filling data gaps are demonstrated by the example of the task of reconstructing the approximate population of the Shelonskaya Pyatina of the considered time period.

Abstract: One of the actual problems of Byzantine studies is the estimation of the size of the Genoese trading community of Constantinople, which played a critical role in the fate of late Byzantium. To solve this problem the historian A.L. Ponomarev proposed to use mathematical methods based on data from indirect sources - notarial deeds preserved in the State Archives of Genoa. These deeds were drawn up to fix commercial transactions, agreements on the creation of commercial partnerships, the hiring of ships, wills, the purchase and sale of houses, goods and people. In addition to the obligatory mention in the deed form of the names of the contracting parties and witnesses to the transaction, it may also, depending on its type, contain the names of guardians, recipients of the will and other third parties.
Thus, these data on the clientele of Genoese notaries represent a rather impressive and valuable array of information, which may indirectly indicate the size of the entire trading Genoese community of Byzantium. To solve this problem, the author of this paper draws on the ideas and methods of the theory of random placements, which is an intensively developing area of mathematical statistics. It is based on constructing a linear estimate of the value and assumes a random sample. The result obtained is compared with the estimate from the previous paper by the author, which is based on another method of mathematical statistics and is quite close to the value of A.L. Ponomarev - 688 people.

Abstract: The author develops a mathematical-statistical approach to the problem of estimating the size of Genoese medieval population in Byzantium. The data source is notarial acts covering commercial partnerships, freightage, wills, purchase and sale of houses, goods and people drawn up in the Genoese colony of Constantinople at the end of the 13th century. The will form has a fairly uniform structure. In addition to the mandatory record of names of the contracting parties and witnesses of the transaction, it may also register names of the third parties. Thus, these data on the clientele of Genoese notaries represent a dataset which may indirectly indicate the size of the entire trading Genoese community of Byzantium. This approach is based on a constructed formalized model that describes the behavior of merchants when visiting and concluding a transaction attested by a notary. This makes it possible to pass in a natural way from the initial to the statistical problem of estimating the size of a finite aggregate and use this mathematical theory for its calculation. In this case, the author applies the approach associated with the use of the maximum likelihood function that is a novelty. The resulting formula allows (with a certain degree of probability) one to estimate the required size of the Genoese population. It is interesting that this estimate, on the whole, coincides with the result of A.L. Ponomarev obtained earlier for the same problem using Zipf's empirical law.

Abstract: The research subject of this article is the mathematical modeling of the process of spatial settlement among medieval rural populations. Due to the heterogeneous features of land in different regions, the distribution of populations is not uniform. Along with the system of ordinary settlements, the presented model examines the system of the centers serving them. As such, there are settlements that have concentrated on themselves the functions of serving the entire surrounding population (for example, tribute collection centers or parish centers). The model assumes that the distribution of the system of centers is not uniform. The aim of the developed model is to describe the laws of such settlement systems. In order to achieve this goal, an innovative variational approach is developed, the essence of whichconsists in considering the process of historical settlement as a self-developing system, characterized by its parameters and needs. The use of the mathematical methods of variation calculations within the framework of this approach allowed the author to find the parameters of the existing systems for establishing centers and to quantitatively describe the relevant phenomena occurring within them. The testing of the proposed model is carried out on the basis of one rural settlement structure from the late 15th - early 16th centuries (Derevskaya Pyatina on the territory of Novgorod). A high degree of correspondence in the obtained theoretical results from empirical data allows the author to consider mathematical modeling as an adequate and convenient auxiliary tool for studying the process of historical settlement.

Abstract: Mathematical modeling is increasingly popular to study spatial distribution of population. This trend is determined by the necessity to study the dynamics of population quantity and density, reconstruct lacking data, search for population displacement factors and evaluate their influence on this process. The current study develops the model describing the system of centers distribution (the settlement structure) of the one-level hierarchy. Such a modeling aims at searching for basic factors and evaluating their influence on the process, associating optimum parameters which characterize the system of centers distribution. The model developed by the author is based on the innovative approach of S.M. Gusein-Zade which makes it possible to describe the regularities in the location (distribution) of heterogeneous settlements and other centers on the territories. The variations calculus methods applied as well as the concept of Pareto optimality allows one to find parameters of the existing systems of centers location and quantitatively describe the phenomena occurring in them. The model has been tested to study a medieval rural settlement and has proven adequate and correct.
It has been demonstrated that the process of free population displacement was caused by two counterbalancing factors: a centripetal one (concentration of settlements around their centers) and a centrifugal one (displacement of population near the farmland).

Abstract: The subject of this study is the formalized classification of the surviving copies of the medieval Slavic text "Zakon Sudnyj Ljudem", which is the oldest transferred monument of Slavic law and one of the earliest texts in the Slavic language. To resolve the difficulty of textological classification, the authors propose a model based on natural assumptions regarding the process of copying texts and have developed a method using the idea of applying the fuzzy set theory. The advantage of the fuzzy approach is the building of a stemma of the existing copies with their given level of reliability, taking into account their possible contamination. The proposed method is based on a formalized analysis of the fuzzy relation preference matrix, formulated as a result of a pairwise textual comparison of copies. To quantify the contribution of every reading discrepancy, a typology of readings was created, as well as an indirect estimation method was developed. This article describes the first experiment of applying the fuzzy genealogical classification method to a large manuscript tradition (57 copies, about 6500 readings). The obtained results as a whole do not contradict the results of the traditional textological analysis or other formalized methods and allow us to specify the grouping of copies and their interrelations. The developed approach is universal and can be applied to the classification of other manuscript texts.

Abstract: The authors demonstrate opportunities and discuss prospects of a new text editing software application of similar origin and general structure. This application is developed to be integrated within a program of fuzzy genealogical classification. The research focus is medieval texts which have long been in use and have been preserved in many variants. The study aims at searching links between different variants of texts that are hidden to experts and their presentation for further expert evaluation. Such an approach adapts and develops fuzzy sets theory means and thus lets us single out close groups within the variants preserved and genealogically link them to any reliability degree desired. The classification proposed bases not only on quantitative data (number of variant readings, texts proximity coefficients), but qualitative parameters as well (weight coefficients of variant readings) accounting for their importance for textological classification that has been ignored in formalized approaches before. Successful work of this software application is sure to provide a researcher with a powerful and handy tool to compare and analyze numerous medieval texts with the help of algorithm based mathematical methods.

Abstract: The article examines the issue of the genealogical classification preserved in the copies of Medieval texts. For its understanding the authors propose an approach based on the use of the theory of fuzzy sets. This approach utilizes the matrix of the fuzzy preference relation, which is founded on the pairwise comparison of the lists with each other. Each element of this matrix is the summation of its components, whose value is determined by the end set of different value factors (types of lection). These factors are considered in their total sum in the form of weight coefficients, which are determined through expert means. In order to eliminate the unavoidable subjectivity in evaluating them, the authors of this work developed an indirect method of expertise. The aim of the proposed method lies in that the given factors are compared pairwise in their value with each other. This way the initial complex problem is substituted by the entirety of more simple ones. Meanwhile the experts operate not with quantitative, but qualitative evaluations. The proposed new approach of expert evaluation allows in a formal way to assess the value of one or another discrepancy in the text. Thus the use of the proposed method plays a key role in the fuzzy classification of the list of Medieval compositions (establishing a genealogical stemming). The use of the examined method is illustrated on a specific example of discrepancy typology.