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Timeline for Unitary condition

Current License: CC BY-SA 4.0

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Nov 18, 2019 at 16:26 comment added LSpice @‍SamZbarsky's comment referenced by @IosifPinelis.
Nov 18, 2019 at 13:57 vote accept Toni Mhax
Nov 17, 2019 at 20:55 history edited Morgan Rogers CC BY-SA 4.0
Added an example.
S Nov 17, 2019 at 19:44 history suggested Toni Mhax CC BY-SA 4.0
You meant min i guess. Tx
Nov 17, 2019 at 19:06 comment added Iosif Pinelis Concerning conjecture 2), Sam Zbarsky's comment shows it is false.
Nov 17, 2019 at 18:32 review Suggested edits
S Nov 17, 2019 at 19:44
Nov 17, 2019 at 18:05 comment added Morgan Rogers The feel of this proof reminded me of the Gershgorin Theorems bounding the spectrum of a matrix in terms of sums of column entries compared with diagonal entries. It's not directly relevant, but may be of interest.
Nov 17, 2019 at 17:57 history edited Morgan Rogers CC BY-SA 4.0
Edited based on comments
Nov 17, 2019 at 17:18 comment added Morgan Rogers Oops yep, good point. I'll edit appropriately.
Nov 17, 2019 at 17:16 comment added Iosif Pinelis I like this answer a lot. However, your conclusion $n |v_{i,i}|^2\le1$ would only be justified if you had $I(\pi_*)\ge1$, whereas you actually have $I(\pi_*)\le1$. Anyhow, you have proved a slightly weaker conclusion, $n |v_{i,i}|^2\le2$, which will imply the OP's conjecture 1) for $n\ge4$; the cases $n=2,3$ should be easy. Also, your proof applies to the more general setting with a general doubly stochastic matrix $(p_{ij})$ in place of the unistochastic matrix $(|u_{ij}|^2)$; see en.wikipedia.org/wiki/Unistochastic_matrix .
Nov 17, 2019 at 16:19 history answered Morgan Rogers CC BY-SA 4.0