ABSTRACT
Suppose a pair is formed of two persons, A and B. In a case where A likes B, B
may not like A. In another case where A likes B very much, B may like A fairly
well. In either case, the relation from A to B is not the same as the relation from
B to A, and we will call the relationship asymmetric. Suppose a pair is formed
of two brands of cars, and consider users of car brand A (say, A-users) and users
of car brand B (say, B-users) at a certain time. After some time, some of the
A-users will switch to brand B, and also some B-users will switch to brand
A. The number of people switching from A to B is usually not the same as
the number of people switching from B to A. In such a case, we call the relation-
ship between brands A and B asymmetric. Consider trade flow between two
countries, A and B. The amount of trade that A imports from B may be larger
or smaller than that which B imports from A. In our terminology, we call such a
relationship asymmetric. When the degree of asymmetry is large, the situation
could become a political issue of trade imbalance.