I was the only admin of a Facebook Messenger group chat, and I left the chat. Now I can’t get back in

Like the question says, I was the sole admin of the Messenger chat. We had the setting enabled where new people had to be approved to join by an admin. Since I left, nobody can approve me to join.

Is there any way an existing member can become an admin? Or is there any way around this so that I can get back in?

keyboard – Can’t move the cursor in text editor with left and right arrow

I’m having an annoying issue and need your help. While typing in a text editor or chat, I can’t move my typing cursor by left and right arrows. However, if I press (command + left/right), the cursor can move to the next word. I think I may unconsciously change a setting somewhere.

Any help is appreciated. Thank you!

ct.category theory – In a rigid monoidal category, why is $W^*otimes V^*$ a left dual of $V otimes W$?

My approach: We want to produce a coevaluation map $c: mathbf{1} rightarrow (V otimes W) otimes (W^* otimes V^*)$ and an evaluation map $e : (W^* otimes V^*) otimes (V otimes W) rightarrow mathbf{1} $ such that the maps

$$r_{Votimes W} circ (1_{Votimes W} otimes e) circ a_{Votimes W, W^* otimes V^*, Votimes W} circ cotimes 1_{Votimes W} circ l_{Votimes W}^{-1}$$

$$l_{W^*otimes V^*} circ (eotimes 1_{W^*otimes V^*} ) circ a_{W^*otimes V^*, V otimes W, W^*otimes V^*}^{-1} circ 1_{W^*otimes V^*}otimes c circ r_{W^*otimes V^*}^{-1}$$

are the identity maps on $V otimes W$ and $W^* otimes V^*$, respectively. Naturally one would want to use the maps $e_V, c_V, e_W, c_W$, so I suggest the following definition of $e$, suppressing the associativity constraint:

$$ e = W^* otimes V^* otimes V otimes W xrightarrow{1_W^* otimes e_V otimes 1_V^*} W^*otimes mathbf{1} otimes W cong W^* otimes W xrightarrow{ev_W} mathbf{1}$$

and similarly

$$ c = mathbf{1} xrightarrow{c_V} V^*otimes V cong (V^* otimes 1) otimes V xrightarrow{1_{V^*} otimes e_W otimes 1_V } V otimes W otimes W^* otimes V^*$$

It can be checked that these give $W^* otimes V^*$ the structure of a left dual by verifying the definition. Then, since all left duals are unique up to unique isomorphism, it follows that $(V otimes W)^* cong W^*otimes V^*$.

unity – X axis not moving right or left

I’ve made a script that should have an x and a y axis, it goes up and down but not left or right; what am I doing wrong?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Mouselook : MonoBehaviour

    public float mouseSensititvity = 100f;

    public Transform playerBody;

    float xRotation = 0f;

    // Start is called before the first frame update
    void Start()
        Cursor.lockState = CursorLockMode.Locked;

    // Update is called once per frame
    void Update()
        float mouseX = Input.GetAxis("Mouse X") * mouseSensititvity * Time.deltaTime;
        float mouseY = Input.GetAxis("Mouse Y") * mouseSensititvity * Time.deltaTime;

        xRotation = mouseX

        xRotation -= mouseY;
        xRotation = Mathf.Clamp(xRotation, -90f, 90f);

        transform.localRotation = Quaternion.Euler(xRotation, 0f, 0f);
        playerBody.Rotate(Vector3.up * mouseY);

        playerBody.Rotate(Vector3.up * mouseX);


DD of LVM Partition to another disk drive not working – no space left on device

I have a vmdk attached to my Linux VM instance (/dev/sda). The disk has 2 partitions, as shown below:

Disk /dev/sda: 17.2 GB, 17179869184 bytes, 33554432 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a6648

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     2099199     1048576   83  Linux
/dev/sda2         2099200    33554431    15727616   8e  Linux LVM

I tried to copy both partitions using the dd command to a new hard disk of the same size attached to the VM (/dev/sdb).
I created 2 partitions on /dev/sdb using fdisk. The first partition is the boot partition (/dev/sdb1), and the 2nd partition is for the LVM root partition (dev/sdb2). I went ahead and ran:

dd if=/dev/sda1 of=/dev/sdb1 bs=1M

and that completed without any errors.

Next a ran an lvdisplay to see the logical volumes on /dev/sda:

 --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                AQn0bI-7gb7-KjdG-v3ls-yO0I-nkjc-E7bfHP
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2018-10-01 15:06:59 -0400
  LV Status              available
  # open                 2
  LV Size                1.60 GiB
  Current LE             410
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                rL4g8k-YYXo-0mi1-0Q2U-fNhF-8Izg-f6wd5C
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2018-10-01 15:06:59 -0400
  LV Status              available
  # open                 1
  LV Size                13.39 GiB
  Current LE             3429
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

I then ran a pvcreate on /dev/sdb2, created a new volume group (centos-02), added /dev/sdb2 to the new volume group, then created logical partitions (root-02, and swap-0sam2) of the exact same size for both the root and swap volumes on /dev/sda2.

I then ran the following dd commands:

dd if=/dev/centos/swap of=/dev/centos-02/swap-02
dd if=/dev/centos/root of=/dev/centos-02/root-02

the copy from root to root2 fails with this message:

dd: writing to ‘/dev/centos-02/root-02’: No space left on device
28082177+0 records in
28082176+0 records out
14378074112 bytes (14 GB) copied, 632.803 s, 22.7 MB/s

Can anyone explain why the dd is saying that? Both logical volumes are exactly the same size, and also, the copy from the old swap volume to new works. Why is the root logical volume copy failing?

Thanks in advance for any advice.

sql server – Is left hash join always better than left outer join?

I have a query that runs quite slow (see below). While searching for a way to improve it we found that the query runs about ten times faster if we replaced the LEFT OUTER JOIN with LEFT HASH JOIN

The result seems to be the same. Is it? In what cases wont it return the same result? What difference are there? Is there something that i should look out for when running a LEFT HASH JOIN instead of a LEFT OUTER JOIN?

SELECT t.foo, t.bar, t.data
FROM (dbo).(Table) as t
LEFT OUTER JOIN (ABC).(ExternalTable) as s ON s.foo = t.foo and s.bar = t.bar and s.data = t.data
WHERE s.foo is null and s.bar IS NULL and s.data IS NULL

mysql – Executando query com subs-consultas e left join

Bom dia!

Tenho duas tabelas

Tabela A:

ID | valor

1 | 20.00
2 | 30.00
3 | 40.00
4 | 50.00

Tabela B

ID | tabela_a_id | valor  | ativo
1. | 1           | 100.00 | 0
2. | 1           | 200.00 | 1

Ao realizar um JOIN eu iria receber duas linhas com os dois registros, porém eu gostaria de saber 1 REGISTRO para cada tabela_a_ID e em forma de colunas eu teria o resultado do join da tabela B então ficaria assim:


ID  | ativo1 |  valor1  | ativo2  | valor2
1   | 0      |  100.00  |    1    | 200.00

Como eu consigo realizar isso usando MYSQL??


itunes – Can’t backup iPhone because no storage space left when there is?

I am trying to backup my iPhone but iTunes complains that I do not have enough free space on my computer to do so.

I don’t believe this is correct however, on my machine I have my Macintosh SSD (which has 90GB remaining), and an additional drive which has 300+GB remaining.

Many years ago I changed my MobileSync directory to a folder in my additional drive as there is a lot more free storage on there. I did this using a Symlink (article here covers how to do so), and it has been working as I can see all the existing backups up until now all stored in my second drive.

I am trying to do a backup of my iPhone now which I believe has around 140GB worth of data to backup, but I get the following error:

enter image description here

I’m not sure why its showing this error because there is no way backup is larger than 300GB, which is how much free storage I have on my second drive (where my backups are stored).

I can confirm the symlink is still there, as when I navigate to the MobileSync folder it directs to my folder made in the second drive.

Finder always opens as a small window on the top left corner of the screen

Finder always opens as a small window on the top left corner of the screen. I adjust the window size, position, but after a while when I open the window again it opens as a small window on the top left corner by sticking to the menu.
This happens in any view mode: list, columns, etc. If I relaunch Finder it helps for a while, but then the problem comes back. It happens in Mojave, Catalina, Big Sur. This is terribly annoying.
Any ideas?