Read More
Date: 29-9-2019
![]()
Date: 25-4-2018
![]()
Date: 28-8-2018
![]() |
A subset of the real numbers is said to be a
set provided
is the countable intersection of open sets. The name
comes from German: The G stands for Gebiet, meaning "area," while the
stands for Durchschnitt, meaning "intersection."
This definition is dual to that of an Fsigma set in the sense that is a
set if and only if its complement
is an
.
Note that both and
sets are fundamental to measure theory. In particular, both types of sets are Borel sets and are considered to be the second level of the so-called Borel hierarchy
REFERENCES:
Royden, H. L. and Fitzpatrick, P. M. Real Analysis. Pearson, 2010.
.
|
|
إدارة الغذاء والدواء الأميركية تقرّ عقارا جديدا للألزهايمر
|
|
|
|
|
شراء وقود الطائرات المستدام.. "الدفع" من جيب المسافر
|
|
|
|
|
المجمع العلمي يختتم مشروع الدورات القرآنية الصيفية في محافظة ذي قار بمشاركة 3750 طالباً
|
|
|