MathOverflow will be down for maintenance for approximately 3 hours, starting Monday evening (06/24/2013) at approximately 9:00 PM Eastern time (UTC-4).
0

Let $X$ be a Banach space, $V$ and $W$ two closed subspaces of $X$ with $W \subset V$. Is it true that $V/W$ is closed in $X/W$?

flag
What are the continous linear functionals that vanish on it? – Charles Matthews Jan 20 2012 at 13:49
1 
This is a trivial test if one has understood the quotient topology. – Martin Brandenburg Jan 20 2012 at 13:51

closed as too localized by Bill Johnson, Charles Matthews, Martin Brandenburg, Andreas Blass, Willie Wong Jan 20 2012 at 14:31

1 Answer

0

Yes, it is closed. Proof: The quotient map $p: X\to X/W$ is open. $U=X\setminus V$ is open. So is $p(U)=(X/W)\setminus (V/W)$.

link|flag

Not the answer you're looking for? Browse other questions tagged or ask your own question.