root – There is something wrong with my process. Someone have acess to my machine?

top - 16:38:24 up 10 min,  1 user,  load average: 0,74, 0,90, 0,58
Tasks: 274 total,   2 running, 272 sleeping,   0 stopped,   0 zombie
%Cpu(s):  4,5 us,  0,8 sy,  0,0 ni, 94,6 id,  0,1 wa,  0,0 hi,  0,0 si,  0,0 st
MiB Mem :   7772,1 total,   5133,3 free,   1266,3 used,   1372,5 buff/cache
MiB Swap:   2048,0 total,   2048,0 free,      0,0 used.   6159,5 avail Mem 



    >   10573 raskolk+  20   0 2347888 225228  96180 S 319,5   2,8   4:51.47
    > chrome                                                                
    > 11105 raskolk+  20   0 5805648 130104  89160 S  77,5   1,6   0:24.87
    > chrome                                                                
    > 11119 raskolk+  20   0 9770,3m 133420  85064 S  14,2   1,7   0:05.54
    > chrome                                                                
    > 4084 root      20   0 1520224 159324  86136 S  13,2   2,0   1:01.95
    > Xorg                                                                  
    > 5206 raskolk+  20   0  834876  56080  40172 S   3,6   0,7   0:09.66
    > gnome-terminal-                                                       
    > 4403 raskolk+  20   0 6148936 416232 148904 S   3,0   5,2   4:11.41
    > gnome-shell                                                           
    > 10434 raskolk+  20   0 3360624 214336 123152 S   1,7   2,7   0:12.82
    > chrome                                                                
    > 
    >     234 root     -51   0       0      0      0 S   1,0   0,0   0:03.98 irq/51-ELAN0B00                                                       
    > 10029 raskolk+  20   0   21512   4260   3460 R   0,7   0,1   0:02.08
    > top                                                                   
    > 10101 raskolk+  20   0 2643180 167524 110840 S   0,7   2,1   0:06.92
    > Web Content                                                           
    > 10578 raskolk+  20   0 1020136  87488  64416 S   0,7   1,1   0:02.43
    > chrome                                                                
    > 
    >      11 root      20   0       0      0      0 I   0,3   0,0   0:00.82 rcu_sched                                                             
    > 6157 raskolk+  20   0 2480064 150240  99980 S   0,3   1,9   0:03.17
    > Web Content                                                           
    > 
    >       1 root      20   0  169968  13424   8776 S   0,0   0,2   0:02.89 systemd                                                               
    > 
    >       2 root      20   0       0      0      0 S   0,0   0,0   0:00.01 kthreadd                                                              
    > 
    >       3 root       0 -20       0      0      0 I   0,0   0,0   0:00.00 rcu_gp                                                                
    > 
    >       4 root       0 -20       0      0      0 I   0,0   0,0   0:00.00 rcu_par_gp                                                            
    > 
    >       7 root      20   0       0      0      0 I   0,0   0,0   0:00.15 kworker/0:1-events                                                    
    > 
    >       8 root      20   0       0      0      0 I   0,0   0,0   0:00.34 kworker/u16:0-ext4-rsv-conversion                                     
    > 
    >       9 root       0 -20       0      0      0 I   0,0   0,0   0:00.00 mm_percpu_wq                                                          
    > 
    >      10 root      20   0       0      0      0 S   0,0   0,0   0:00.02 ksoftirqd/0                                                           
    > 
    >      12 root      rt   0       0      0      0 S   0,0   0,0   0:00.01 migration/0                                                           
    > 
    >      13 root     -51   0       0      0      0 S   0,0   0,0   0:00.00 idle_inject/0                                                         
    > 
    >      14 root      20   0       0      0      0 S   0,0   0,0   0:00.00 cpuhp/0                                                               
    > 
    >      15 root      20   0       0      0      0 S   0,0   0,0   0:00.00 cpuhp/1                                                               
    > 
    >      16 root     -51   0       0      0      0 S   0,0   0,0   0:00.00 idle_inject/1                                                         
    > 
    >      17 root      rt   0       0      0      0 S   0,0   0,0   0:00.18 migration/1                                                           
    > 
    >      18 root      20   0       0      0      0 S   0,0   0,0   0:00.02 ksoftirqd/1

ho.history overview – Widely accepted mathematical results that were later shown to be wrong?

The Busemann-Petty problem (posed in 1956) has an interesting history. It asks the following question: if $K$ and $L$ are two origin-symmetric convex bodies in $mathbb{R}^n$ such that the volume of each central hyperplane section of $K$ is less than the volume of the corresponding section of $L$:
$$operatorname{Vol}_{n-1}(Kcap xi^perp)le operatorname{Vol}_{n-1}(Lcap xi^perp)qquadtext{for all } xiin S^{n-1},$$
does it follow that the volume of $K$ is less than the volume of $L$: $operatorname{Vol}_n(K)le operatorname{Vol}_n(L)?$

Many mathematician’s gut reaction to the question is that the answer must be yes and Minkowski’s uniqueness theorem provides some mathematical justification for such a belief—Minkwoski’s uniqueness theorem implies that an origin-symmetric star body in $mathbb{R}^n$ is completely determined by the volumes of its central hyperplane sections, so these volumes of central hyperplane sections do contain a vast amount of information about the bodies. It was widely believed that the answer to the Busemann-Problem must be true, even though it was still a largely unopened conjecture.

Nevertheless, in 1975 everyone was caught off-guard when Larman and Rogers produced a counter-example showing that the assertion is false in $n ge 12$ dimensions. Their counter-example was quite complicated, but in 1986, Keith Ball proved that the maximum hyperplane section of the unit cube is $sqrt{2}$ regardless of the dimension, and a consequence of this is that the centered unit cube and a centered ball of suitable radius provide a counter-example when $n ge 10$. Some time later Giannopoulos and Bourgain (independently) gave counter-examples for $nge 7$, and then Papadimitrakis and Gardner (independently) gave counter-examples for $n=5,6$.

By 1992 only the three and four dimensional cases of the Busemann-Petty problem remained unsolved, since the problem is trivially true in two dimensions and by that point counter-examples had been found for all $nge 5$.
Around this time theory had been developed connecting the problem with the notion of an “intersection body”. Lutwak proved that if the body with smaller sections is an intersection body then the conclusion of the Busemann-Petty problem follows. Later work by Grinberg, Rivin, Gardner, and Zhang strengthened the connection and established that the Busemann-Petty problem has an affirmative answer in $mathbb{R}^n$ iff every origin-symmetric convex body in $mathbb{R}^n$ is an intersection body. But the question of whether a body is an intersection body is closely related to the positivity of the inverse spherical Radon transform. In 1994, Richard Gardner used geometric methods to invert the spherical Radon transform in three dimensions in such a way to prove that the problem has an affirmative answer in three dimensions (which was surprising since all of the results up to that point had been negative). Then in 1994, Gaoyong Zhang published a paper (in the Annals of Mathematics) which claimed to prove that the unit cube in $mathbb{R}^4$ is not an intersection body and as a consequence that the problem has a negative answer in $n=4$.

For three years everyone believed the problem had been solved, but in 1997 Alexander Koldobsky (who was working on completely different problems) provided a new Fourier analytic approach to convex bodies and in particular established a very convenient Fourier analytic characterization of intersection bodies. Using his new characterization he showed that the unit cube in $mathbb{R}^4$ is an intersection body, contradicting Zhang’s earlier claim. It turned out that Zhang’s paper was incorrect and this re-opened the Busemann-Petty problem again.

After learning that Koldobsky’s results contradicted his claims, Zhang quickly proved that in fact every origin-symmetric convex body in $mathbb{R}^4$ is an intersection body and hence that the Busemann-Petty problem has an affirmative answer in $mathbb{R}^4$—the opposite of what he had previously claimed. This later paper was also published in the Annals, and so Zhang may be perhaps the only person to have published in such a prestigious journal both that $P$ and that $neg P$!

c++ – What’s wrong with my midpoint?

I was extremity annoyed by the lengthy, edge-case-galore explanation of integer mindpoint here, so I made my own simple 2’s complement version. I present it for your judgement, since senpai at libstdc++ didn’t notice me T_T

The general idea is to carry out a + (b-a)/2 in a wider singed integer that won’t ever overflow.
Say a and b are N bit integers. Consider them as imaginary singed (2’s complement) N+1 bit integers. The obvious magic of 2’s complement is that we can carry out addition/subtraction as usual, so first we obtain the lower N bits of the hypothetical N+1 bit difference,

Unsigned diff = Unsigned(b) - Unsigned(a);

working with unsigned type to avoid signed overflow UB. We don’t really have the +1 bit, so just imagine sign extension also happens. We only care about lower N bits anyway since we know the final half difference has to fit there. Problem is – we can’t do division in this straightforward way, so we have to branch, based on the sign of the final result.

  • If N+1 bit difference was negative (highest/sign bit set), we jump through hoops:
    Unsigned negative_2x = -diff; // Negate/abs (2's complement approved as subtraction 0-diff). negative_2x /= 2; // Divide (it works cause sign bit is now guaranteed 0).
    Now we can fit this halfed difference back into our original N bit signed int, so we convert it back and negate to restore the original sign.
    Integer negative = -Integer(negative_2x);
    Converting first is important to avoid signed overflow UB again. If original Integer was unsigned this still works, since the wrapping behavior is consistent with 2’s complement.

  • Otherwise if difference was positive, it fully fit in N bits unsigned, and half of it should fit in signed, no hoops:
    Integer positive = diff / 2;

The actual branch looks like to encourage conditional move, not that compilers care…

auto overflew = b < a;
return a + (overflew ? negative : positive);

Full version here
passes all the libstdc++ and libc++ unit tests for integers.

Windows 10 menu fonts (sometimes others) look wrong

On many programs (some examples are VLC, VirtualBox) the menu fonts and sometimes other fonts look incomplete. here is the menu from VLC:

VLC

I won’t post the VirtualBox image, but the fonts are bad on the entire window. I’ve tried various things I’ve looked up (including substitute fonts) without any luck. Any ideas on how to fix this?

Thanks in advance.

boot – Booting Oh no! Something went wrong Error

Latley, ive been having abit of issues with gnome and decided to re-install it on Pop_os! 20.10 and suddenly the OS crashed. I keep getting a white screen telling me that the bootup dosent work and to contact a sys admin. I booted up a terminal in order to update and upgrade my distro + clean some files but I get the error saying ‘cdrom://Pop_OS20.10_Groovy_Gorilla_-releaseamd64(20201022) groovy release’ does not have a Relese file. And also underneath the error: ‘Updating from such a repositry can’t be done securely, and is therefore disabled by default.’
‘See apt-secure(8)…’

If anyone has any ideas im willing to try anything, thanks.

Apache virtualhost is redirecting to the wrong virtualhost

I am trying to implement a second domain within an existing digitalocean droplet.

Because I’m on DO, I followed the answer by ryanpq on this thread: https://www.digitalocean.com/community/questions/is-it-possible-to-install-another-wordpress-on-droplet

Similar to the commenters on that thread, my newer site redirects to my existing site (even after changing the DocumentRoot and Directory appropriately).

Here are my configs:

Within /etc/apache2/sites-enabled, I have 4 files: 000-default-le-ssl.conf 000-default.conf example1.conf example2.conf

000-default.conf and example1.conf are copies.

example1.conf looks like so:

# Added to mitigate CVE-2017-8295 vulnerability
UseCanonicalName On

<VirtualHost *:80>
        ServerAdmin webmaster@localhost

        ServerName example1.io
        ServerAlias www.example1.io

        DocumentRoot /var/www/html

        <Directory /var/www/html/>
            Options FollowSymLinks
            AllowOverride None
            Require all granted
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
RewriteEngine on
RewriteCond %{SERVER_NAME} =www.example1.io (OR)
RewriteCond %{SERVER_NAME} =example1.io
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} (END,NE,R=permanent)

example2.conf looks like so:

<VirtualHost *:80>
        ServerAdmin webmaster@example2.com

        ServerName example2.com
        ServerAlias www.example2.com

        DocumentRoot /var/www/example2

        <Directory /var/www/example2/>
            Options FollowSymLinks
            AllowOverride All
            Require all granted
        </Directory>

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

my directory structure looks like /var/www/html and /var/www/example2

Within the DNS control panel, I created new A and CNAME records. The A record points to the IP address of the older, existing, site (so, example2.com directs to 128….)

Going to example2.com redirects me to example1.io.

What am I missing?

sharepoint online – Getting “Sorry, something went wrong with adding the app. Click to retry.” when adding a SPFx library to a site

I made a SPFx library component and deployed it to my tenant app catalogue (as a non tenant wide publish). I then tried to add the app to one of my sites but it says Sorry, something went wrong with adding the app. Click to retry.. How can I add it, or for this type of app does only tenant wide install work?

combinatorics – Prove that this summation has a surprising result! (Or prove me wrong, it is possible that the pattern does not hold)

Essentially, prove the following summation:

$$sum_{i=0}^{2x} {{2x choose 2i}{2i choose i}{2x-2i choose x-i}} = {2x choose x}^2$$

I came across this while attempting question 6 of this paper (BMO1 2019) and while I’m sure there are easier solutions to the problem, this summation seemed interesting in itself. Very similar to this summation is the following:

$$sum_{i=0}^{x} {{2i choose i}{2x-2i choose x-i}} = {2}^{2x}$$

Which I also do not have a proof for. The second one can also be thought of as going down the middle of Pascal’s triangle and adding the products of opposite ends of the triangle.

Proofs of either summation, ideally using mathematical ideas which the BMO1 is based around (so basically pre-calculus), would be much appreciated.

18.04 – Batter indicator showing wrong percentage and charging and discharging time also random

I purchase a new laptop and i install xubuntu. its working perfectly but battery indicator showing random value for charging and discharging.

**my Os details** 

*Operating System: Ubuntu 18.04.5 LTS

        Kernel: Linux 5.4.0-54-generic

  Architecture: x86-64*

Other information about power

ram@sonti:~$ upower -d

Device: /org/freedesktop/UPower/devices/line_power_ACAD

native-path: ACAD

power supply: yes

updated: Monday 23 November 2020 08:19:29 AM IST (1353 seconds ago)

has history: no

has statistics: no

line-power

warning-level:       none

online:              no

icon-name:          'ac-adapter-symbolic'

Device: /org/freedesktop/UPower/devices/battery_BAT1

native-path: BAT1

vendor: Hewlett-Packard

model: PABAS0241231

model: PABAS0241231

serial: 41167

power supply: yes
updated: Monday 23 November 2020 08:41:29 AM IST (33 seconds ago)
has history: yes
has statistics: yes
battery

present:             yes

rechargeable:        yes


state:               discharging

warning-level:       none

energy:              24.4264 Wh
energy-empty:        0 Wh
energy-full:         41.3003 Wh
energy-full-design:  41.0508 Wh
energy-rate:         13.3164 W
voltage:             11.248 V
time to empty:       1.8 hours
percentage:          59%
capacity:            100%
technology:          lithium-ion
icon-name:          'battery-good-symbolic'

History (charge):
1606101089 59.000 discharging

History (rate):
1606101089 13.316 discharging

Device: /org/freedesktop/UPower/devices/DisplayDevice

power supply: yes

updated: Monday 23 November 2020 08:41:29 AM IST (33 seconds ago)

has history: no

has statistics: no

battery

present:             yes

state:               discharging

warning-level:       none

energy:              24.4264 Wh

energy-full:         41.3003 Wh

energy-rate:         13.3164 W

time to empty:       1.8 hours
percentage:          59%

icon-name:          'battery-good-symbolic'

Daemon:

daemon-version: 0.99.7

on-battery: yes

lid-is-closed: no

lid-is-present: yes

critical-action: HybridSleep
And laptop detail laptop detailenter image description here

dnd 5e – Are the Storm Giant’s strength scores in the Monster Manual wrong?

Storm Giants are Huge creatures, not Medium.

The encumbrance rules neglect the size of a creature when calculating if it is encumbered or heavily encumbered. While this is true, the maximum capacity of a Storm Giant is not the same that a human would have given it a Strength score of 29.

Quoting the rules on lifting and carrying (Player’s Handbook, page 176):

Carrying Capacity. Your carrying capacity is your Strength score multiplied by 15. This is the weight (in pounds) that you can carry, (…).

(…)

Size and Strength. Larger creatures can bear more weight, whereas Tiny creatures can carry less. For each size category above Medium, double the creature’s carrying capacity and the amount it can push, drag, or lift. (…)

The rules on creature size categories are on page 191 of the Player’s Handbook:

$begin{array}{|l|c|}
hline
textbf{Size} & textbf{Space} \
hline
text{Tiny} & 2,frac{1}{2},text{by},2,frac{1}{2},text{ft.} \
text{Small} & 5,text{by},5,text{ft.} \
text{Medium} & 5,text{by},5,text{ft.} \
text{Large} & 10,text{by},10,text{ft.} \
text{Huge} & 15,text{by},15,text{ft.} \
text{Gargantuan} & 20,text{by},20,text{ft. or larger} \
hline
end{array}
$

Huge size is two size categories above Medium size; therefore, the maximum weight a storm giant could lift is not 435 lbs., but four times that (i.e. 435 lbs., doubled twice): a total of 1,740 lbs.


Remember that the Encumbrance rules are a variant rule and are meant to apply to playable races (Small- to Medium-sized creatures). The DM is free to adjust those values to be doubled for each size above Medium to keep it plausible to be used for larger creatures, to mirror the increase in carrying capacity for larger sizes.

Also, they are monsters. The rules for players do not necessarily apply the same way for NPCs.