Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 17261

Matrix theory is the study of matrices as concrete objects, rather than as abstract linear operators between vector spaces (whose study belongs to linear algebra). For instance, this involves matrix factorizations and decompositions, nonnegative matrices and Perron-Frobenius theory, Schur complements, structured and special matrices, matrix functions and equations.

1 vote
Accepted

Choi type matrix condition for completely positivity on a certain operator system spanned by...

The answer is no : Let $U_1 = I$, where $I$ is the identity and $U_2$ linear independent to $I$ such that $U_2^* + U_2 \ge 0$ . Then choose $\phi(U_1) = I$ and $\phi(U_2) = -I$ .
jjcale's user avatar
  • 2,753
18 votes

Is the linear span of special orthogonal matrices equal to the whole space of $N\times N$ ma...

Let $S$ be the span of $SO(N)$ . Then it's obvious that if $A \in S$ and $D_1, D_2 \in SO(N)$ then $D_1^{-1} A D_2 \in S$ . Therefore it's enough to show that $B := diag(1,0,...0) \in S$ . If $N$ i …
jjcale's user avatar
  • 2,753
7 votes
Accepted

Well known matrix inequality?

The desired inequality follows from an majorisation argument : According to Bhatia Matrix Analysis Corollary III.4.6 we have : $log \lambda(AB) \succ log \lambda^\downarrow(A) + log \lambda^\uparro …
jjcale's user avatar
  • 2,753