Timeline for Modified interlacing of eigenvalues

14 events

when toggle format	what		by	license	comment
Apr 29, 2016 at 4:50	vote	accept	Sry
Apr 28, 2016 at 21:40	answer	added	Nik Weaver		timeline score: 1
Apr 27, 2016 at 15:17	comment	added	Nik Weaver		Okay, I misread the problem. I don't know the answer, but did you notice that you could put $B = 2v$ without changing nonzero eigenvalues? So the question is about interlacing between $\left[\matrix{A& v\cr v^T&0}\right]$ and $\left[\matrix{A& 2v\cr 2v^T& 0}\right]$.
Apr 27, 2016 at 7:24	comment	added	Sry		I have edited the question to be more elaborated. Yesterday also I put those details in a comment but that comment is no more visible and I don't know why :(
Apr 27, 2016 at 7:16	history	edited	Sry	CC BY-SA 3.0	added 154 characters in body
Apr 27, 2016 at 7:07	comment	added	Sry		Yes, It can be zero. In particular, take $A=0$ and $A$ is a $n$ order principal submatrix of $D$. I don't understand why you took $n\le4$
Apr 26, 2016 at 16:09	comment	added	Nik Weaver		$P$ is any order $n$ principal submatrix of $D$ $\ldots$ so if $n \leq 4$, could $P$ be the zero matrix?
Apr 26, 2016 at 7:50	history	edited	Sry	CC BY-SA 3.0	deleted 2 characters in body
Apr 26, 2016 at 7:33	history	edited	Sry	CC BY-SA 3.0	added 5 characters in body
S Apr 25, 2016 at 13:54	history	suggested	Amir Sagiv		added relevant subject tags
Apr 25, 2016 at 13:32	review	Suggested edits
S Apr 25, 2016 at 13:54
Apr 25, 2016 at 12:32	history	edited	Sry	CC BY-SA 3.0	added 1 character in body
Apr 25, 2016 at 12:11	review	First posts
Apr 25, 2016 at 12:33
Apr 25, 2016 at 12:03	history	asked	Sry	CC BY-SA 3.0