Defensive alliances in graphs: a survey

A set $S$ of vertices of a graph $G$ is a defensive $k$-alliance in $G$ if every vertex of $S$ has at least $k$ more neighbors inside of $S$ than outside. This is primarily an expository article surveying the principal known results on defensive alliances in graph. Its seven sections are: Introduction, Computational complexity and realizability, Defensive $k$-alliance number, Boundary defensive $k$-alliances, Defensive alliances in Cartesian product graphs, Partitioning a graph into defensive $k$-alliances, and Defensive $k$-alliance free sets.Comment: 25 page

Techonology Based Strategic Alliances: A Turkish Perspective

Strategic alliances can be as simple as two companies sharing their technological and/or marketing resources. In this context, strategic alliances help firms in an entrepreneurial way by allowing them to reorganize their value chain activities more effectively. Business alliances can assist organizations to acquire the means to compete within an ever complex and changing environment and it provide firms with market knowledge, open up access to know-how and technology. This study focuses on the technology related alliances from 2002 to 2005 in Turkey.Strategic Alliances; Techology Based Alliances; Compatitive Power

Persistence of and interrelation between horizontal and vertical technology alliances

We examine how and to what extent the propensity to be engaged in alliances with different partner types (suppliers, customers and competitors) depends on prior alliance engagement with partner firms of the same type (persistence) and prior engagement in alliances with the other partner types (interrelation). We derive hypotheses from a combined competence and governance view of collaboration, and test these on an extensive panel dataset of innovation-active Dutch firms during 1996-2004. We find persistence in alliance engagement of all three types of partners, but customer alliances are more persistent than supplier alliances. Most persistent are joint supplier and customer alliances, which we attribute to the advantages of value chain integration in innovation processes. Positive interrelation also exists in vertical alliances, as immediate past customer alliances increase the propensity to engage in supplier alliances and vice versa. On the other hand, while prior engagement in horizontal (competitor) alliances increases the propensity to engage in vertical alliances, this effect only occurs with a longer lag. Overall, our findings are highly supportive of the idea that alliance engagement with different partner types is heterogeneous but interrelated. Our analysis suggests that the inter-temporal relationship between different types of alliances may be as important as their simultaneous relationship in alliance portfolios.R&D collaboration, technological partnerships, innovation, path dependency

Recent mobile telecommunications alliance formation

During the year to end-January 2005, the resurgence of takeover activity in the mobile telecommunications industry 1 has attracted media attention. However, by focusing on takeovers, the willingness of companies in the sector to collaborate through alliance and joint venture formation is in danger of being overlooked. These alliances, none of which are more than two years old, can be variously interpreted. They could signify a return to expansionary behaviour by operators motivated by the desire to capture lucrative roaming traffic or retain key customers. Alternatively the alliances may be motivated by the desire to compete more effectively with Vodafone, which is arguably the only mobile operator with a global footprint. This paper is structured as follows. In the initial section, the six alliances that have been formed are described. Particular attention is paid to the membership and resulting scale of these alliances, as well as to the motives for their formation. The first sub-section focuses on those alliances that are largely scale orientated in motivation, while the second concentrates on those that are more technologically orientated. These alliances are then discussed in detail and conclusions are drawn

Managing ambiguity of strategic alliances – the role of negotiations

Strategic alliances have become an important part of most company's portfolios. In an era of rapid technological change, the ever rapidly changing competitive landscape, and the globalization of competition more and more companies are choosing to participate in alliances. With their competitors entering into alliances, firms are often faced with few choices other than that of forming alliances to nullify the potential advantage of their rivals. The high failure rates are mirrored in the demise of some alliances that have garnered widespread publicity. This paper studies the increasing importance of negotiations in faceing and managing the ambiguity of the process of alliances and tries to formulate some rules to be followed in order to achieve the right balance in strategic alliances.strategic alliances, negotiation success, ambiguity, competition, failure

Case Studies of Strategic Alliances in U.S. Beef Production

Calf marketing, commercial beef carcass, and natural/implant-free beef strategic alliances were examined via case study to determine alliance structure and whether each addressed risk, transaction costs, capital availability, and other concerns. All alliances were structured differently through vertical or horizontal coordination, and each had been established within the past 12 years. Alliance administrators reported that an advantage to cow-calf producers was higher cattle prices received relative to producers outside the alliances. The alliances reduced transaction costs and increased information flow among segments. Alliances did not specifically address risk or increased access to capital for technology adoption or expansion purposes.cattle industry, industry structure, risk, strategic alliances, transaction costs, Agribusiness, Livestock Production/Industries,

Fight Alone or Together? The Need to Belong

Alliances often face both free-riding and hold-up problems, which under- mine the effectiveness of alliances in mobilizing joint fighting effort. Despite of these disadvantages, alliances are still ubiquitous in all types of contests. This paper asks if there are non-monetary incentives to form alliances, e.g., intimidating/discouraging the single player(s) who is/are left alone. For this purpose, I compare symmetric (2 vs. 2) and asymmetric (2 vs. 1) contests to their equivalent 4-player and 3-player individual contests, respectively. We find that alliance players in symmetric (2 vs. 2) contests behave the same as those in equivalent 4-player individual contests. However, in asymmetric (2 vs. 1) contests, stand-alone players were strongly discouraged to exert effort (especially the females), compared to the 3-player individual contests. Alliance players may have anticipated this effect and also reduced their effort, if alliances share the prize according to the merit rule. Behavioural factors such as the need to belong can help reconcile the "paradox of alliance formation"

STRATEGIC EFFECTS OF AIRLINE ALLIANCES

This paper looks at the endogenous formation of airline alliances bymeans of a two-stage game where first airlines decide whether to form analliance and then fares are determined. We analyze the profitability and thestrategic effects of airline alliances when two complementary alliances,following different paths, may be formed to serve a certain city-pair market.The formation of a complementary alliance is shown to hurt outsiders and thatfares decrease in the interline market. Contrary to what might be expected, wefind that complementary alliances are not always profitable, even in thepresence of economies of traffic density. The interplay between market size, thedegree of product differentiation and the intensity of economies of trafficdensity determines whether the market equilibrium entails no alliances, a singlealliance or a double alliance.complementary airline alliances, economies of traffic density, product differentiation

Information alliances in contests with budget limits

We study the role of information exchange through alliances in a framework with contestants who have binding budget limits and know their own budget limit but are incompletely informed about other contestants' budget limits. First, we solve for the Bayesian Nash equilibrium. Then we consider the role of information exchange through alliances. Contestants learn the budget limits of all players who are within the same alliance, and then decide independently about their own contest efforts. This type of alliance formation is beneficial for alliance members and neutral for players who do not belong to the alliance. Also, a merger between alliances is beneficial for their members. Further, we consider merger between alliances and discuss the set of stable combinations of alliances. --Contest,budget limits,incomplete information,alliances,information sharing

The impact of industry group culture on the development of opportunism in cross-sector alliances

Over the last two decades the world economy has dramatically transformed, with strategic alliances and partnerships across industrial and global boundaries becoming an important means to maintaining and regaining competitive positioning. In spite of an increase in partnership activity, alliances continue to face problems fuelled by factors such as partner opportunism, and cultural incompatibility. This paper highlights the emergence of opportunism in alliances arising from cross-sectoral partners’ differences in cultural values and norms. The literature indicates that cultural differences are important factors for understanding the behaviour of managers across sectors