@taro

I noticed just now that I asked the same question in another post.
https://www.mapleprimes.com/questions/225321-Internal-Representation

Sorry.

@Carl Love 

Thank you for your answer.
And, I'm sorry for being late on writing this reply.

I began to study about maple again.
I found two things. First, I could use English better last year than I am writing now.  
Second is that I repeat the same thing as last year.
A few days ago, I found that seq(i,i=1..5) returns _EXPSEQ(1, 2, 3, 4, 5).But, as I can get its list by surrounding it with [  ], there seems no problem.
lprint(seq(i,i=1..5) ) ; returns 1, 2, 3, 4, 5,  which has no problem.

taro

@Carl Love 

Thank you for your explanation.
Surely, `or` is not Inert, as if it is so, it should need the command "value" to have the function executed.
`or` only has us need one more return, after `or` (A, B) returns "A or B."

And, thank you for the use of % in %subs.

@Carl Love 

I'm sorry. I don't understand anything about VV's question.
And, I can't write anything appropriate, but to write that `or` means symbol. So `or` (x,y) means just a sequence of
words of "or, x and y", leaving its evaluation to people who so wrote.

But, I have a question to you.

Can you please tell me how to use %subs?
subs(a = 0, x or y) is the output of

restart;
x := a=0;
y := b=0;
%subs(a= 0, 'x or y');

But, I can't understand what is done with its code.

@vv 

restart;
x := a=0:  y := b=0:
subs(a=0, x or y);

false

So, subs, which has only a function of incerting something,  as well as eval does not work, and
I cannot find any document about this operation of "or."
 

@Carl Love 
Thank you for your explanation of the meaning of "situations where something mathematical happens to e."
On the other hand, I understands what kind of outcome applears through using subs: first subs works so that 
the 0 is inserted into x's inDiff(sin(x),x), before Diff(sin(x),x) is calculated.

@Carl Love

Then, what do you think is the problem of VV?
I'm glad if you explain it.

@Carl Love 

Thank you for your teaching. I wish your further kindness to give me an additional answer.
I couldn't understand what you are writing in 1. So, I am very happy if you show me an example 
where something mathematical happens to e that has me feel it better to use eval rather than subs.

@Preben Alsholm

For the problem of _EXPSEQ appearing at solve(x^2-1,x), 
with "interface(typesetting=standard)" as you write, that problem is avoided, which is similarly done with 
switching from Extended to Maple standard at Preference->Display->Typesetting level.
Thank you for your suggestion. But,  the problem you write of _EXPSEQ(1,-1) not being changed occurrs to me as well.

@Rouben Rostamian  @Carl Love

I used Rouben's mw.mw and ascertained that Build IDs match with each other.
And, with pretty print, the same thing as to Rouben applies to me.

@Carl Love

f := proc (x) options operator, arrow, function_assign; piecewise(x < 0, 3^(-(1/3)*x^2), .5*2^(5^(-x))) end proc;
R(x) := int(f(t), t = x .. x+l):
L(x) := int(f(t), t = x-l .. x):
D(x) := (R(x)-L(x))/(R(x)+L(x));
eval(D(x),{l=3,x=5});

returns

-0.28372415e-2+0.*I

, not zero with my mape2017 of mac.

@Carl Love 

Thank you for your teaching.

@Kitonum 

Though your plane in R^3: 2*x+3*y-z=4 is not the same as that of op: 2*x-3*y+z = 4.
But, I think that it is because you tried to show me that there is a case that the answer 
is not a plane, but a line.  

Surely, in
 <-9,-15,24>*x + <-12,-20,32> * y +  <20,32,-52>, 

 <-9,-15,24> and <-12,-20,32> are on the same line. So, in this case, the original plane degenerates 
to a line pararel to <-9,-15,24>.

Thank you for teaching me a lot.

@Carl Love 

Thank you.
I was trying to find a help page which will help me in having some knowledge about 
how to handle arrays, for example how to change

C1 := [111, 112, 121, 122, 211, 212, 221, 222]
to
C2 := [111, 211, 121, 221, 112, 212, 122, 222].

That is, I wondered how I can change array to rtable in C_order, which is 1 dimensional, then again change it to array, and then change it to 1 dimensional rtable in Fortran_order.
I thought the help page you kindly taught me might help in such purposes.

@Carl Love

Thank you Carl,
After reading what you wrote to me, I again thought that Maple is very interesting.
There are lot of things yet I haven't heard yet.
Thank you for having me notice those things.

And, I'm sorry for having forgotten to check the Voteup.