The article analyzes current legislative maintenance of territorial communities’ cooperation in Ukraine in cross-border space. It outlines cross-border cooperation within the Euroregion through concluding agreements on cross-border cooperation in certain spheres, establishment and development of mutually advantageous contacts between them and choosing its new forms. Opportunities to create the cross-border cooperation body to perform functions assigned to it by territorial communities, their representative bodies and local executive authorities according to its competences and in the manner prescribed by the Law of Ukraine are revealed. Cross-border cooperation is suggested to be strengthened through development and implementation of joint initiatives, activities, projects, programs and strategies in certain spheres. This stipulates coordination of cooperation and accumulation of resources doe the defined period in order to jointly conduct relevant activities. It is proposed to define cross-border grouping in legislative manner as voluntary combining of entities and/or participants of cross-border cooperation in Ukraine and neighbouring countries, stipulated by the agreement on cross-border cooperation. Cross-border groupings can be in particular the following: European groupings for Territorial Cooperation – combining of cross-border entities of Ukraine and respective entities of neighbouring countries – EU members with legal personality according to national legislation of EU member state, where its headquarters are located; Euroregional Cooperation Groupings (ECG) – form of cross-border cooperation body with legal personality in accordance with country’s national legislation, where its headquarters are located; cross-border partnership, where cross-border cooperation participants act in accordance with agreement provisions in order to implement joint projects and programs and to solve common problems; cross-border cluster. 

voluntary groupings, bordering territories, territorial communities, cross-border space, cross-border cooperation 

The article outlines the directions to research the mechanisms related to examining of existing economic institutes, explaining and predicting economic or social consequences and constructing of mechanisms to achieve the defined goals. The necessity of expanding the mechanisms in terms of stimulus of individuals, who have key information and their own goals and may not have an incentive to conduct themselves relevantly, is stressed.
The classification of mechanisms of economic entities’ interrelation is developed by the following parameters: by design; by entities (designers); by formalization; by interaction object. It is mentioned that dichotomous division of all possible interrelation types into two opposite types – cooperation and competitiveness – is the most common. Cooperation of economic entities in cross-border space is proposed to be classified by the following parameters: by the nature of basic institute; by formalization; by legitimization; by cooperation form.
Peculiarities of economic entities’ interrelation through cross-border markets are defined by its nature: occasional interrelation; established interrelation. It is found that according to the theory of interaction the cross-border market participants not only act in the fixed conditions, but also have the possibility to become the entities, which form the structure of the given market and create the rules of its functioning as well as form the new markets. Economic entities’ cooperation is characterized through cross-border markets using the conventional economic approach and interaction approach. It is found that in the course of cooperation at cross-border markets the relatively stable status hierarchies are formed compared to other markets (regional, local), because constant monitoring mechanism is not implemented and, therefore, the entities cannot mutually position themselves in relation to each other. However, there also exist the mechanisms of active adoption of leading entities’ conduct or mimetic (imitative) isomorphism. It is defined that cross-border links can be defined mostly as stable and simultaneously selective interactions, which help the entities in their striving for control over actions of other entities.Economicagreementisthemostessentialelementofmarketinteraction, kind of a core. It stipulates availability of not less than two participants, which establish the exchange terms on the basis of two interdependent mechanisms – structural and interactive.
The proposed classification of mechanisms of economic entities’ interrelation in cross-border space is essential in the process of research and detection of existing mechanisms of economic entities’ interrelation in cross-border space and construction of new ones in order to activate interaction of economic entities in cross-border space and eventually obtain positive synergic effect on both sides of the border. 

classification of mechanisms, mechanisms of cooperation, cooperation in cross-border space, cross-border market 

The development of cross-border cooperation has shown that current cross-border cooperation forms do not allow to perform all tasks. It makes condition for new forms emerging, and each form should be created and operate according to special procedures.

The aim of the paper is describing the forms of interaction of economic actors in the cross-border space and presenting the main characteristics of that forms.

Many different forms of interaction are used in the cross-border cooperation. List of used forms depends on the chosen model of cross-border interaction. Each interaction form requires some transaction costs. Economic actors select the most effective models of interaction among interchangeable models. The effectiveness of the cross-border cooperation models should be evaluated by transaction costs.

Selection of the cross-border interaction model is based on a comparison of total transaction costs for different combinations of the used forms of interaction. The high variability of transaction costs for cross-border interaction causes a change of feasibility of cross-border cooperation, and it influence on the territorial localization of cross-border market.

The interaction in cross-border area is realized by economic actors of cross-border market, central and regional authorities, and international organizations. It forms a particular institutional environment. The transformation of the institutional environment of neighboring countries can both facilitate and hinder the process of cooperation in cross-border area.

Formation and development of effective cross-border interactions in Ukraine depends on the institutional environment. Today institutional environment of cross-border cooperation are not similar in different parts of the Ukrainian border. During the direct interaction the subjects of cross-border markets, in addition to general obstacles, faced with specific obstacles: customs and other charges; restrictions applicable to the movement of goods across the border; different legal, tax and customs systems, different opportunities to use allowance and privileges according to the regional and national legislation of neighboring countries; different quality of regional infrastructure etc.

Economic conditions, including institutional environment, influence the level of transaction costs. It promotes selecting the most effective forms (according to cross-border cooperation participants viewpoint), which in turn changes the institutional environment.

Cross-border cooperation participants follow certain interaction rules only on their own accord. Selection of the cross-border interaction forms usually are resolved by mutual agreement of all the participants. However, sometimes one participant forces other participants for achieving their consent.

Selection of cross-border interaction forms is bounded rational because rationality of the cross-border economic actors is limited by the information they have, the cognitive limitations of their minds, and the finite amount of time they have to make a decision. 

cross-border cooperation, forms of cross-border cooperation, participants of cross-border cooperation, cross-border space, the localization of cross-border market, models of cross-border inteaction, transaction costs, institutional environment 

Bordering trade and its localization place is defined. The bordering trade entities are classified by their activity. The peculiarities of bordering trade in the cross-border space of Ukraine with the EU are examined, particularly in Ukrainian-Polish, Ukrainian-Slovak and Slovak-Polish regions. The influence of signing and approval of Small bordering movement agreement with adjacent countries - EU members on the development of bordering trade is analyzed. The interest of adjacent countries-EU members in the organization of bordering trade in cross-border space with Ukraine is outlined. 

bordering trade, bordering trade entities, cross-border flow, bordering territory, small bordering movement 

The essence of transborder market and its place in the system of regional and international markets is outlined. The features of transborder region, which influence the functioning of transborder market, are exposed. The conceptual approaches to the research of the transborder market environment, which engulf the principles, the basic tasks of research, the algorithm of realization of analysis, information sources and methods, are proposed with the purpose of exposure and analysis of trends, factors and terms that influence the development of competitive environment in a transborder region. The main provisions provided by the research may be used for the development of methodological recommendations for the transborder market environment analysis. 

transborder region, transborder market, boundary region, regional market, transborder market environment, transborder cooperation 

Influence of the border tradе on the vital functions of frontier habitants on the basis of sociological research, and also tangent regional researches has been considered. A conduct and motivation of people in different aspects (depending on age, nationality, social state, education, places of residence and others like that) and terms which determine mass character of those busy in the frontier, the forming of transborder streams on the basis of social features have been studied. Trends of perfection of normativelegal base of organization of the border tradе in the conditions of participation of Ukraine in WTO have been offered. 

border tradе, boundary territory