@Carl Love Thank for your response. And sorry for my precedent mixup.

As anames](user) noticed, I did mixup "assumption" with "assigment". The initial question was right and the answer of dharr 6671 is exactly what I needed. Thank you for your kind help.

@Carl Love  I define two objects:

>a:=2;

>b:=sin(x);

>about(indices(`property/OrigName`));
Function about:  describe what is known by assume about
######## ######  an object or a property

INPUT:  an arbitrary number of objects or properties

For example: about( x );
             about( LowerTriangular, UpperTriangular )

This is not what I want. I want to know what is the value of "a" and "b" when I am at the bottom of my worksheet and I cannot see what  I have defined.

But thank you for those commands.

@Scot Gould Since I use a Canadian-French keyboard (qwerty), the shortcut keys do not work. Nor the international Ctrl + Alt + O. So I have put the "overscript" template in my Favorites.  It is starting to be crowded.  I have asked to get many Favorites palettes that we could choose which one you want to use with a drop-down menu in the palettes. The choice depends on what you are working on at the moment.  Maybe we will see this one day.

@acer I see that I should have uploaded my worksheet in which I was doing exactly what you have done.  Yesterday, I had worked with Maple for two hours when I decided to try what was in the PDF document. Unfortunately, it was not working at all. The input was done like you did, but when I press Enter, the output was exactly the same as the input.  And no, I was not in the mode "non-executable math."

Maple 2024 is doing things funny when I am working for more than an hour, or even less.  Many times, I have to quit Maple and restart it so it works like it should. I have not written a bug in the beta website because it is clear, as this example is another case of it, that it seems to happen only on my machine for an unknown reason.

I use Windows 11 Professianal x64 23H2 but I doubt that it has something to do with it. At least, I had a kind answer form Scot..

@Scot Gould Thank you for your reponse and the link for the files. I really appreciate.

Let me thank you for all those years of implication in Maple. Your work in the Physics packages was tremendous. I wish you the best for your future projects.

@acer The functional P(z) is very practicle and so simple.  Thank you for the idea.  I have a worksheet with an example.Convert_to_exp.mw

@Carl Love Thank you for telling me what it is called. Now I know. At least I knew that Iterator was probably where the solution was. I love that last solution. She taught me a lot about using Maple. Thank you very much.

In readingt a book on diferential forms (Fortney - A Visual Introduction to Differential Forms and Calculus on Manifolds), I stumble on a lot of definitions that I never saw. And another one is what it is called in the book page 94:

At page 94, it is stated the definitiion of the wegde product (See Shuffle.png)

I know about the finite symmetric group Sn. But it's the way the author uses the (k,l)-shuffle, the symbol v sigma (k+l), etc. Does someone can explain this to me and is there a way to do it in Maple so I can multiply the right terms. If you have the book, pages 95-97 is full of symbols of permutation sigma. I get the feeling of what I have to do but I would prefer to better understand it. Or maybe this is not the place for this. In that case, my apology.

Thank you both acer and mmcdara for your solutions.

I don't have to do that with a lot of elements in both sets so performance is not a question. The answer is exactly what I need. And by looking at the solution, it is clear that I would not have been able to solve it by myself. Once again, the pertinence of MaplePrimes has been shown.

Thank you!

@rlopez  Thank you very much Robert for the clarification. It is clear that I will be registered for your webinars. It’s a nice, very appropriate coincidence that your webinar will be about the Differential Geometry package.

I would like to take the opportunity to ask you if you could suggest me some good books on the subject. I can't wait to see the connection with tensors, general relativity and quantum field theory. I send you my best regards. Mario

@acer Thank you. I love the second one. Interresting to see that something so simple by hand becomes more complex on the computer.

Very interresting ways of doing it.

Many times I feel that my plots would be better if it were possible to change the default for the color of the grid. This is, for me, very evident in the examples that you have shown above. When you want to have two 3D plots on the same plot, of course. But even if there is only one plot.

I would add that I would very appreciate if, for a 3D plot, it was possible to create this kind of grids in the background of the plot (not the plot as is). We only have those options: boxed, normal, frame, or none. We could call it "3Dgrid".

What do you think of all this?