For any simple connected graph $G=(V,E)$, a defensive alliance is a subset $S$ of $V$ satisfying the condition that every vertex $vin S$ has at most one more neighbour in $V-S$ than it has in $S$. The minimum cardinality of any defensive alliance in $G$ is called the alliance number of $G$, denoted $a(G)$. In this paper, we introduce a new type of alliance number called $k$-strong alliance numb...

A defensive alliance in a graph is a set $S$ of vertices with the property that every vertex in $S$ has at most one moreneighbor outside of $S$ than it has inside of $S$. A defensive alliance $S$ is called global if it forms a dominating set. The global defensive alliance number of a graph $G$ is the minimum cardinality of a global defensive alliance in $G$. In this article we study the global ...

We consider complexity issues and upper bounds for defensive alliances and strong global offensive alliances in graphs. We prove that it is NP-complete to decide for a given 6-regular graph G and a given integer a, whether G contains a defensive alliance of order at most a. Furthermore, we prove that determining the strong global offensive alliance number γô(G) of a graph G is APX-hard for cubi...

We study the process of wealth creation by alliances and relate it to the quality of governance of firms. We argue that alliances increase firm’s operating flexibility, reduce the agency costs related to the free-cash flows as well as the agency costs related to the distortion in the allocation of capital within the firm. Given the constraints on the use of free cash flows, managers at the helm...

We examine how industrial clustering affects biotechnology firms’ innovativeness, contrasting similar firms not located in clusters or located in clusters that are or are not focused on the firm’s technological specialization. Using detailed firm level data, we find clustered firms are eight times more innovative than geographically remote firms, with largest effects for firms located in cluste...

In this paper we examine the influence of strategic technology alliances on organisational learning. From an empirical perspective we examine the preand post-alliance knowledge bases of allying firms. We find that the pre-alliance knowledge base overlap of the allying firms has an inverted U-shaped relationship with the degree of learning taking place in the alliance. Alliances established for ...

Strategic alliances attempt to create a cooperative association between two or more firms to share resources such as product design, production, marketing or distribution. Alliances can be used to avoid the rigidity of some organisational forms, such as mergers and takeovers, and to gain access to knowledge and skills otherwise not available. Despite the rapid growth in the formation of allianc...

In many emergent markets, cross-industry alliances are necessary to develop and market new products and services. The resource-based view suggests that firms form alliances to access or acquire valuable, rare, non-imitable and non-substitutable resources, and that such access determines the level of profits. Hence, firms confronted with the choice between partners with strong versus partners wi...