Geography Reference
In-Depth Information
Assignees
Patents
Inventors
Top
: Bipartite graph of assignees (
,
,
,
), patents (1 to 5) and inventors (A to M), with lines
linking each patent to the respective inventors and assignees.
Source:
Breschi and Lissoni (2004, 2009).
Figure 16
.
1
Bipartite graph of patents and inventors
(A to M). For example, patent 1, assigned to company a, has been produced by a team
comprising inventors A, B, C, D and E. It is reasonable to assume that, because of their
collaboration in a common research project, those i ve inventors are
socially linked
by
some kind of knowledge sharing. The existence of such a linkage can be graphically rep-
resented by drawing an undirected edge between each pair of inventors, as in the bottom
part of Figure 16.1.
Repeating the same exercise for each team of inventors, we end up with a graph repre-
senting the network of all inventors. This allows us to measure how tight is the connec-
tion between each pair of patents. In order to see how, we i rst give a few dei nitions:
1.
For any pair of inventors, one can measure the distance between the two by calculat-
ing the so-called
geodesic distance
. The geodesic distance is dei ned as the minimum
number of edges that separate two distinct inventors in the network.
5
In Figure 16.1,
for example, the geodesic distance between inventors A and C is equal to 1, whereas
the same distance for inventors A and H is 3. While A and C shared directly their
knowledge while working on patent 1, A and H are more likely to have exchanged
some word-of-mouth technical information through the mediation of other actors
(such as B and F).
2.
Any two inventors may belong to the same
social component
or to
socially discon-
nected components
. A component of a graph can be dei ned as a subset of the entire
graph, such that all nodes included in the subset are connected through some path.
In Figure 16.1, for example, inventors A to K belong to the same component,
