EULER DIAGRAM

An 'Euler diagram' is a way of representing how sets overlap, similar to the more commonly-known Venn diagram.
It is named after its inventor Leonhard Euler[1]. Unlike a Venn diagram, it does not have to contain all possible zones (where a zone is defined as the area of intersection of the sets it shows). Thus, an Euler diagram can define a universe of discourse, i.e. it can define a system whereby certain intersections are not possible or are taken as agreed as not necessary to be considered, and therefore need not be shown on the diagram. In other words, the Euler diagram can represent degenerate conjunctions.
A Venn diagram, on the other hand, shows all possible combinations of conjunctions. A Venn diagram for the system above would show the "unconsidered" zone and, if necessary, mark it specially. Thus, a Venn diagram containing the attributes for ''Animal'', and ''Mineral'' would have to contain an intersection where something was both animal and mineral - even though all readers would know that this intersection was impossible (i.e. known to be empty simply by the ''definition'' of "Animal" and "Mineral").

Contents

See also

See also

★ Johnston diagram