Timeline for Properties of Zero Line-Sum Matrices
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
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| Apr 24 at 18:43 | comment | added | valle | Related: math.stackexchange.com/questions/4904882/… (I posted the question before realizing this was here) | |
| Nov 4, 2019 at 6:03 | vote | accept | Manfred Weis | ||
| Feb 16, 2018 at 20:06 | answer | added | Peter Heinig | timeline score: 7 | |
| Feb 16, 2018 at 19:22 | history | edited | Peter Heinig | CC BY-SA 3.0 |
Grammatical corrections (comma, capitalizations). Abbreviation set in normal font, not math-mode.
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| Feb 16, 2018 at 19:13 | history | edited | Manfred Weis | CC BY-SA 3.0 |
replaced the former 0-Stochastik projection matrix with Zero Line-Sum matrix
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| Feb 16, 2018 at 6:33 | comment | added | Manfred Weis | @GerryMyerson if "line" covers "row" and "column" then that is good alternative to my doubly "0-Stochastic". | |
| Feb 16, 2018 at 6:13 | comment | added | Gerry Myerson | How about "zero line-sum matrices"? | |
| Feb 16, 2018 at 6:00 | comment | added | Manfred Weis | @GerryMyerson I would be happy about a better name for those matrices (I just learned that projection matrix has a special meaning. What "my" matrices can do, is to remove constants that have been added to all elements of a column (when multiplying from the left) or to all elments of a row (when multiplying from the right), so I am tempted to call them "cyclic difference matrix" or maybe there is also the possibility to damp or enhance certain frequencies per row or column and thus an attribute relating to "Fourier" would be more appropriate. | |
| Feb 15, 2018 at 21:54 | comment | added | Gerry Myerson | So these "doubly stochastic projection matrices" are neither doubly stochastic nor projection matrices. | |
| Feb 15, 2018 at 15:11 | history | edited | Manfred Weis | CC BY-SA 3.0 |
clarified the loose meaning of projection
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| Feb 15, 2018 at 13:05 | comment | added | Jochen Glueck | @Manfred Weis: Let us consider the matrix $M =\begin{pmatrix} 1 & -1 \\ -1 &1 \end{pmatrix}$ The columns and rows sum up to $0$, but $M^2 \not= M$. What projection associated to $M$ do you have in mind? | |
| Feb 15, 2018 at 13:01 | comment | added | Manfred Weis | @JochenGlueck as the rank of those matrices can't be full, there must be a kernel that is mapped 0 and I am convinced that in that case one has a projection matrix. | |
| Feb 15, 2018 at 12:57 | comment | added | Manfred Weis | @FedericoPoloni my only restriction would be, that the entries are between -1 and +1; rational entries with small denominators and matrices with high rank would be preferrable to me. | |
| Feb 15, 2018 at 12:36 | comment | added | Federico Poloni | Do you have any constraint on the value or sign of their elements? | |
| Feb 15, 2018 at 12:34 | comment | added | Jochen Glueck | Could you please specify what you mean by "of the projections they define"? There are matrices whose rows and columns all sum up to $0$, but which are not projecctions. | |
| Feb 15, 2018 at 12:19 | history | asked | Manfred Weis | CC BY-SA 3.0 |