Two more important notions can thus be defined.

The notion of a complete semilattice is defined in different ways.

Different notions of closeness can be defined, leading to the difference among these proposals.

His notion of a liberal society was almost defined by difference and contradiction.

This notion can also be defined locally, i.e. for small neighborhoods of points.

The former notions can then be defined in terms of causal processes.

The above definition is useful if the notion of open set is already defined.

In rough set theory, the notion of dependency is defined very simply.

These notions can also be defined with respect to other logics.

The notion of a real form can also be defined for complex Lie groups.