Abstract
The location of the industrial R & D facility is apt to be attracted by the locations of its headquarter or its production plants. In this paper, certain concepts and properties from the theory of digraph are introduced for the description of close proximity of R & D facilities to the headquarter or plant, and industrial R & D is then examined within the context of intra-firm locational linkages. The analysis is derived from questionnaire data for machinery industries in Japan. It concludes that 'internal' locational factors are of primary importance in industrial R & D locations.
