2.3 Mapping cyberspace over a visualization media
An exact match from the set 
to set 
is a mapping that has a corresponding relation tuple (element) in 
for each relation in 
. A mapping fulfilling this requirement is called a homomorphism from 
to 
such that
.
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Consider that a mapping exists wherein there is a one-to-one correspondence between the vertices in 
and the vertices in a subgraph of 
such that a pair of vertices are adjacent in 
if and only if the corresponding pair of vertices are adjacent in the subgraph of 
. This is in fact the condition for a monomorphic mapping:
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which can also be described as a isomorphic mapping to a subset 
from the relation 
such that
.
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Note that all these morphism problems have been shown to be NP-complete and therefore cannot be solved exactly in polynomial time.