Timeline for Proving equality of a vector multiplication example
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 3, 2019 at 15:26 | comment | added | Federico Poloni | Yes, that's it! | |
| Dec 3, 2019 at 14:58 | comment | added | Guoyang Qin | Interesting. I just checked the Wikipedia and found Kronecker product, I thought a scalar multiple of a matrix, say $\lambda \mathbf{A}$, can be written as $\mathbf{A}\otimes[\lambda]_{1\times1}$. Do I get what you meant? | |
| Dec 3, 2019 at 12:31 | comment | added | Federico Poloni | (Incidentally, I think that many of these apparent discrepancies arise from the habit to write in first-year linear algebra courses $\alpha v + \beta w$ for linear combinations rather than $v\alpha + w\beta$...) | |
| Dec 3, 2019 at 12:28 | comment | added | Federico Poloni | @GuoyangQin Various $matrix\cdot scalar$ operations can be considered as $matrix \otimes scalar$, if I get what you mean. | |
| Dec 3, 2019 at 10:41 | comment | added | Guoyang Qin | Thanks. It also answers an implicit question that puzzled me - the ambiguity of a scalar and a $1\times 1$ matrix with the same value. Writing as $vector \cdot scalar$ is indeed a great tip, since one can take the scalar as a $1\times 1$ matrix, and then they will become associative. But how about $matrix \cdot scalar$? I feel this is somewhat a consistency issue of scalar multiplication broadcasting vs. matrix product. It seems the former cannot be fully compatibilized into the latter. | |
| Dec 3, 2019 at 10:29 | vote | accept | Guoyang Qin | ||
| Dec 3, 2019 at 9:33 | comment | added | Federico Poloni | Oops, sorry mods, I didn't notice this was on MO rather than MSE, probably I shouldn't have answered. I see no point in deleting this now anyway. | |
| Dec 3, 2019 at 9:27 | history | answered | Federico Poloni | CC BY-SA 4.0 |