basic properties of a limit along a filter
Theorem 1.
Let be a free filter (non-principal filter) and be a real sequence.
- (i)
If then .
- (ii)
If exists, then .
- (iii)
The -limits are unique.
- (iv)
provided the -limits of and exist.
- (v)
provided the -limits of and exist.
- (vi)
For every cluster point
of the sequence there existsa free filter such that . On the other hand, if exists, it is a cluster point of the sequence .