# pseudodifference

## Primary tabs

Keywords:
difference,complement
Synonym:
pseudo difference
Type of Math Object:
Definition
Major Section:
Reference
Groups audience:

## Mathematics Subject Classification

### An other formula for pseudodifference?

Pseudodifference of lattice L elements a and b is defined by the
formula:
a \* b = min { z in L | a <= (b /\ z) }.

Now one more formula:
a # b = \bigcup { x in L | x <= a and (x /\ b) = 0 }
(where 0 is the least lattice element).

Questions:
1. How "a # b" is called?
2. When a # b = a \* b?
--
Victor Porton - http://www.mathematics21.org
* Algebraic General Topology and Math Synthesis