Databases Reference
In-Depth Information
both being our friend is an indicator that with respect to each other they may be socially
similar.
From his analysis, Granovetter noted that a subgraph upholds the
strong triadic closure
property
if it has a node
A
with strong relationships to two other nodes,
B
and
C
.
B
and
C
then have at least a
weak
, and potentially a
strong
, relationship between them. This is
a bold assertion, and it won't always hold for all subgraphs in a graph. Nonetheless, it is
sufficiently commonplace, particularly in social networks, as to be a credible predictive
indicator.
Strong and Weak Relationships
We're not going to define
weak
and
strong
relationships, because they're specific to each
domain. In a social communications network, a strong social relationship might be said
to exist between friends who've exchanged phone calls in the last week, whereas a weak
social relationship might be said to connect friends who've merely observed one-
another's Facebook status.
Let's see how the strong triadic closure property works as a predictive aid in a workplace
graph. We'll start with a simple organizational hierarchy in which Alice manages Bob
and Charlie, but where there are not yet any connections between her subordinates, as
shown in
Figure 7-12
.
Figure 7-12. Alice manages Bob and Charlie
This is a rather strange situation for the workplace. After all, it's unlikely that Bob and
Charlie will be total strangers to one another. As shown in
Figure 7-13
, whether they're
high-level executives and therefore peers under Alice's executive management or
whether they're assembly-line workers and therefore close colleagues under Alice acting
as foreman, even informally we might expect Bob and Charlie to be somehow connected.
