Databases Reference
In-Depth Information
in it together, which can be a socially amicable arrangement that engenders camaraderie
as in
Figure 7-18
.
Figure 7-18. Alice, Bob, and Charlie are all workmates
In
Figure 7-17
and
Figure 7-18
the triadic closures are idiomatic and constructed with
either three
WORKS_WITH
relationships or two
MANAGES
and a single
WORKS_WITH
rela‐
tionship. They are all
balanced
triadic closures. To understand what it means to have
balanced and unbalanced triadic closures, we'll add more semantic richness to the model
by declaring that the
WORKS_WITH
relationship is socially positive (because coworkers
spend a lot of time interacting), whereas
MANAGES
is a negative relationship because
managers spend overall less of their time interacting with individuals in their charge.
Given this new dimension of positive and negative sentiment, we can now ask the ques‐
tion “What is so special about these balanced structures?” It's clear that strong triadic
closure is still at work, but that's not the only driver. In this case the notion of
structural
balance
also has an effect. A structurally balanced triadic closure consists of relation‐
ships of all strong sentiments (our
WORKS_WITH
or
PEER_OF
relationships) or two rela‐
tionships have negative sentiments (
MANAGES
in our case) with a single positive rela‐
tionship.
We see this often in the real world. If we have two good friends, then social pressure
tends toward those good friends themselves becoming good friends. It's unusual that
those two friends themselves are enemies because that puts a strain on our friendships.
One friend cannot express his dislike of the other to us, because the other person is our
friend too! Given those pressures, it's reasonably likely that ultimately the group will
resolve its differences and good friends will emerge.
This would change our unbalanced triadic closure (two relationships with positive sen‐
timents and one negative) to a balanced closure because all relationships would be of a
positive sentiment much like our collaborative scheme where Alice, Bob, and Charlie
all work together in
Figure 7-18
.
