## Why is this language *not* pumpable? (language = arbitrary word followed by exact same arbitrary word)(pumping lemma for context-free-languages)

language = arbitrary word followed by exact same arbitrary word = u * u (with u being out of non-empty words of alphabet {0, 1} )
(sorry for the formatting, see screenshot-link for conventional/clear expression)

The purpose is to prove that the given language is not a context-free-language (using the pumping lemma).

So i thought that this language should definitely be pumpable, since you can choose x and z as corresponding parts in one of the u/"halves". So if word to be pumped is "0101" then you choose e.g. x=1 (0101) and z=1 (0101) and the remaining parts that stay static are assigned with u=0 (0101), y=0(0101), and v=empty.
If pumped zero-times/i=0 word reads: 00
i=1: 0101
i=2: 011011
i=3: 01110111
(and so on)

(For more complicated words you would need to use all three (u, y, v), but the basic principle would still be that x and z are assigned corresponding parts of the word and u,y,v would be assigned the remainder. (This doesn’t work for the extremely small words 00,01,10,11 that would become empty when zero-pumped, but as long as the exceptions are finite / of finite/fixed number this isn’t a problem AFAIU.)
Clearly this is wrong, but can anybody explain how/why?

## German. Believe it or not.

Hi guys, believe it or not:
though I have been working with GSA SER for a couple of years now and my mother tongue is German, I never had to do a German campaign. Always only English.

Now is the first time and I’m looking for tips. Are there any special lists, any specific engines that will increase my chances?
Is there something like SERengines? (On first looking through I only found some German guestbooks and that is so 1990s internet)

## Bash script – user input ‘not an identifier:’

I am new to bash scripting but I am trying to write a script that creates a react app amongst other things. In the script I would like to pass a variable in the the npx create-react-app .. command. When I run my script I get an error saying ‘ReactAppInitialisation.sh:12: not an identifier: app-name’. Where am I going wrong? many thanks!

printf "${green}What would you like to call your new react app?\n" read app-name npx create-react-app "$  {app-name}" 

## Is the language of all TMs *not* accepting a given string, Enumerable?

Is the following language in RE?
$$L = \{\langle M\rangle : M\text{ is a TM that does not accept }010\}$$

I could use Rice’s Theorem with the property $$P = \{L : 010\text{ is not in }L\}$$ to show it isn’t in R, but how do I show it is in RE?

## Suround 4.0 sound works, stereo mode not. Ubuntu 16.04

My output sound only works in 4.0 mode. In stereo mode is not active (cannot even change volume).

I use Ubuntu 16.04. My sound card is C-Media CMI8768.

Why I want to change to stereo mode? It will probably fix problems with sound in Youtube. Now some video don’t have any sound.

## Network manager applet shows ‘not connected’, and one unmanaged Wired connection, internet working

I have no experience configuring network manager by text configs, used only GUI. When moving mouse over NM tray icon there are tooltip “Not connected”, however I see one connection then clicking it – “Wired unmanaged”. Internet working fine.
I make new ethernet connection with priority 10 but it not appear in NM applet menu.

I have change NM config, as suggested in other questions:

[ifupdown] managed=true 

Question is: how to connect by new created ethernet connection, or at least make “wired” connection managed?
Ubuntu 18.04 cinnamon

## Real exponential field with restricted analytic functions: $\mathbb R_{an, exp, log}$ has quantifier elimination, but $\mathbb R_{an, exp}$ does not.

At a talk sometime ago a result was presented, which I believe originates from:

van den Dries, Lou; Miller, Chris, On the real exponential field with restricted analytic functions, Isr. J. Math. 85, No. 1-3, 19-56 (1994). ZBL0823.03017.

At some point it was mentioned that $$\mathbb R_{an,exp,log}$$ admits quantifier elimination while $$\mathbb R_{an,exp}$$ does not. Here $$\mathbb R_{an,exp}$$ is the theory of the (ordered) real exponential field with function symbols for all restricted analytic functions. Then of course $$\mathbb R_{an,exp,log}$$ is just adding a function symbol for logarithms.

Someone in the audience remarked that $$log(x)$$ (or more precisely, its graph) is quantifier-free definable by $$x = exp(y)$$. Then a fairly simple formula was presented to show why you really need $$log$$ as a function symbol for quantifier elimination, and there is my question: I just cannot remember or reconstruct that formula. So what would be a simple example of some formula in this setting that is not equivalent to a quantifier-free formula in $$\mathbb R_{an,exp}$$?

I am probably missing something obvious here, but now it’s haunting me.

## Is there anyway to prove the precedence of ‘not’ and ‘==’

Is there an example code to demonstrate the precedence of ‘not’ and ‘==’, thanks.

I tried using some way but looks like there is no any difference

I updated the micro data (open graph protocol) 7 days ago – and when I try to attach the pixel to the catalogue it is still greyed out and says ‘not ready’.

The pixel is firing, and I’ve ran the Facebook debugger for my site – and it seems to be pulling through the correct data… can anyone advise anything else to look out for?

There doesn’t seem to be a contact form for Facebook Business when I visit their ‘client contact’ section. And sending a message to Facebook Business through Messenger just gets an automated response…

## Ansible 2.6.2 remote user working but become is not. Config issue?

When attempting to run an ansible module on a destination server (via become) the ssh connection does not appear to be doing a “sudo” to become the application-owner user. The correct remote user is being used but the remote user is not doing “sudo” to become the app-owner account. The config used and command run are described below.

I am expecting to be able to run adhoc ansible commands and playbooks on the destination server.

The destination server has 2 users. User “myapp” that owns the directories and the daemons of the application we’re attempting to control. The user “inuser” has /usr/bin/sudo setup in their nologin permitted functions and has /bin/nologin as their shell in /etc/passwd. The “inuser” user has NO OTHER commands/functions in their nologin permitted functions (and it will be difficult to get any additional commands into nologin).

On the controller server, we’re running ansible as user called “build”. The /home/build/.ansible.cfg file looks like this:

[build@ecombuild01 ~]$echo ""; grep -v "#" ~/.ansible.cfg | grep -v "^$  "  [defaults] inventory      = /sites/utils/local/ansible/hosts library        = /sites/utils/local/ansible/modules/ module_utils   = /sites/utils/local/ansible/module_utils/ remote_tmp     = /sites/utils/tmp/ansible local_tmp      = /sites/utils/tmp/ansible forks          = 50 poll_interval  = 3 transport      = smart module_lang    = C gathering = explicit gather_subset = virtual gather_timeout = 4 roles_path    = /sites/utils/local/ansible/roles host_key_checking = False timeout = 4 remote_user = inuser log_path = /sites/utils/local/var/log/ansible.log private_key_file = /home/build/.ssh/rsa_sudo display_skipped_hosts = False deprecation_warnings = False bin_ansible_callbacks = True nocows = 1 retry_files_enabled = False allow_world_readable_tmpfiles = True [privilege_escalation] become=True become_method=sudo become_user=myapp become_ask_pass=False [paramiko_connection] pty=False [ssh_connection] ssh_args = -q -C -o ControlMaster=auto -o ControlPersist=60s control_path_dir = /sites/utils/tmp/.ansible/sockets scp_if_ssh = smart sftp_batch_mode = True [accelerate] [selinux] [colors] [diff] context = 3 

When I attempt to run a module, I am seeing the following output:

[build@buildserver:/home/build]  ansible -m attApache ecomtest03 -a "action=status" -b --become-method=sudo --become-user=atg -vvv  ansible 2.6.2   config file = /home/build/.ansible.cfg   configured module search path = [u'/sites/utils/local/ansible/modules']   ansible python module location = /sites/utils/Python-2.7.15/lib/python2.7/site-packages/ansible   executable location = /sites/utils/bin/ansible   python version = 2.7.15 (default, Aug 14 2018, 11:48:06) [GCC 4.4.7 20120313 (Red Hat 4.4.7-18)] Using /home/build/.ansible.cfg as config file Parsed /sites/utils/local/ansible/hosts inventory source with script plugin META: ran handlers <ecomtest03> ESTABLISH SSH CONNECTION FOR USER: inuser <ecomtest03> SSH: EXEC ssh -q -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o 'IdentityFile="/home/build/.ssh/rsa_sudo"' -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o User=m06721 -o ConnectTimeout=4 -o ControlPath=/sites/utils/tmp/.ansible/sockets/0b70ddf0be ecomtest03 '/bin/sh -c '"'"'( umask 77 && mkdir -p " echo /var/tmp/ansible-tmp-1554317228.92-158661897220269 " && echo ansible-tmp-1554317228.92-158661897220269=" echo /var/tmp/ansible-tmp-1554317228.92-158661897220269 " ) && sleep 0'"'"'' <ecomtest03> (255, '', '') ecomtest03 | UNREACHABLE! => {     "changed": false,      "msg": "Failed to connect to the host via ssh: ",      "unreachable": true }