front end – Symbol Identity stays Blue when used inside a Merge and does not evaluate

when I start a fresh session of Mathematica

” Version”, “12.1.1 for Microsoft Windows (64-bit) (June 19, 2020)”

” Release ID”, “ (6959458, 2020061902)”

Type in a Input Cell


The Identity is sometimes not suggested and when typed in fully it remains Blue.
Executing the code results in Identity unevaluated.
When editing the code again and retyping Identity it does appear and can be selected or typed.
When executed it works and keeps working. I noticed this behavior also for other thing but forgot to write them down..

It’s weird. Any thoughts?

regex – How to replace decimal symbol Comma to decimal symbol Dot above bars in chart?

I would like to change comma decimal to dot decimal for numbers that have decimals but don’t know how to do that inside Powerpoint. I’m aware of changing Windows setting outside of Powerpoint but I need it inside. The source of data cannot be changed to dots. I already tried but everything gets corrupted, including entire Y axis. I did some research and find out some trick could be used with Regex, whatever this is but I don’t know how and where exactly to use it. Could anyone please tell me how to change comma decimal to dot decimal? Problem is shown below (i have version pro 2013):


Trump who defends the confederate flag and  tweeted a video of a guy yelling “white power” thinks “Black Lives Matter” is a symbol of hate?

When Trump has a chance to attack Democrats he acts with speed and focus. But when he learned that Russia was offering bounties on US soldiers he ignored it, and even lobbied for Russia to rejoin the G8 (currently the G7).


This is a far bigger scandal than Benghazi but conservatives will ignore it because they are partisan traitors with hatred in their hearts. 

Construct a dfa and nfa for a set of strings on{0,1} : the left most symbol differs from the right most one and odd length string

Construct dfa and nfa for a set of string 0,1 such that left most and right most element are different and odd length string
Can you plss draw it

Is the Languague which contains all TMs which write the blank symbol at firs by the given input w decidable?

Consider the problem of determining whether a Turing machine M on an input w writes the blank symbol at first. Is this decidable ?

dnd 5e – What is the lore behind why soul coins have the symbol of Bhaal on them?

We only get one side of the soul coin in official material

As far as I know, the only depiction of the soul coin in official D&D 5e material appears in Baldur’s Gate: Descent into Avernus in Appendix C:

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The depictions of the other side of the coin appear to originate from this tweet from Jim Zub, a writer of multiple D&D comics, who claims to have contributed to the design of the soul coin and its addition to the adventure module.

enter image description here

As far as I can tell, the skull and blood droplets side of the coin never appeared in the book or any other official source.

In terms of a connection to Bhaal, there is nothing in the lore about Bhaal having anything to do with soul coins, or really the Nine Hells in general in any major capacity.

What does a "message with a small circle on in the bottom right hand corner" symbol mean on Samsung’s call logs?

I noticed in my text log, one text message has a small circle in the bottom right hand corner.

enter image description here

It almost looks like a wheel, but other text messages don’t.

What does this mean?

context free – Design a CFG that generates the language { x in {a,b}* | the length of x is odd and its middle symbol is a b }

I am trying to design a context-free grammar that generates the language { x in {a,b}* | the length of x is odd and its middle symbol is a b }.

This is really confusing me, I’m having trouble with making sure that b is always in the middle. Any help?

number theory – Dirichlet L-function associated to Kronecker symbol

The Fourier coefficients of the genus 2 Eisenstein series on the Siegel upper half-space are given by sums over Cohen functions. The Cohen function contains as a multiplicative factor a Dirichlet L-function $L_{D_0}(2-w)$ associated to the Kronecker symbol $left(frac{dot{}}{D_0}right)$, where $D_0$ is the discriminant of the quadratic field $mathbb Q(sqrt D)$ corresponding to the non-positive half-integral summation index
$T=begin{pmatrix} a& b/2\ b/2 & cend{pmatrix}infrac 12mathbb Z^{2times 2},$
$D=b^2-4acleq0$ and $w$ is the weight of the series.
The exact formulas are given in arXiv:1502.00557, p. 60 or arXiv:1310.1745, p. 7. The Mathematica function implementing Dirichlet L-series is DirichletL. However, I am unsure how to relate the Kronecker symbol to the modulus and especially index in the argument of DirichletL, especially given that the index seems to depend on the chosen convention. Any help is appreciated!

matrix – Set: in part assignment is not a symbol

This is probably a basic question but I am new to Mathematica, so please help me out here.

I have the following piece of code:

lmax = 2;
arrlen = lmax + 1;
xarr[x_] = Array[x^# &, arrlen, 0];
parr[p_] = Array[p^# &, arrlen, 0];
arr[x_, p_] = Join[xarr[x], parr[p]];
mboot[x_, p_] := Outer[NonCommutativeMultiply, arr[x, p], arr[x, p]]

Now, I want to set a few particular elements of mboot[x,p] to 0. But when I try, for example:


I get an error saying Set: mboot[x,p] in the part assignment is not a symbol.

It would be great if someone could help me figure out what is going wrong and how I can fix it.