As I remember one can embed the display commands.
So you can try something like this, (I hope it works, I can not try it now.) 
...

L[1,1]:=display(p1,p2):
...

display(L);

It is nice that it also works without dx and  in other languages (not just with the word  integrate).

First, I tried this pattern with both of commands (evalindets and subsindets), and it doesn't work:

subsindets(f3,'sqrt(anything)',t->g);

a*g+b+g

Is this the correct answer from this command (as designed)?

First, I tried this pattern with both of commands (evalindets and subsindets), and it doesn't work:

subsindets(f3,'sqrt(anything)',t->g);

a*g+b+g

Is this the correct answer from this command (as designed)?

Nice. Thanks. Interestingly, I also thought of using some command like this, for example PDEtools[dchange] but I had no success with it and I gave it up.

Nice. Thanks. Interestingly, I also thought of using some command like this, for example PDEtools[dchange] but I had no success with it and I gave it up.

Thanks.

This gives a solution in this case, but  in more general cases it doesn't work. For example if the expression contains the subexpression also in nominator and denominator like this f3:=a/sqrt(x-y)+b+sqrt(x-y); Ok, I can apply another subs to the get the final solution, but it is not so handy, when I have  a big expression.

I hoped that evalindets can do it, but  I get wrong result with it.

Thanks.

This gives a solution in this case, but  in more general cases it doesn't work. For example if the expression contains the subexpression also in nominator and denominator like this f3:=a/sqrt(x-y)+b+sqrt(x-y); Ok, I can apply another subs to the get the final solution, but it is not so handy, when I have  a big expression.

I hoped that evalindets can do it, but  I get wrong result with it.

Thanks for your suggestion.

I have checked the help before. Actually my problem is that I expect Maple to perform such straigthforward conversions automatically,

Thanks for your suggestion.

I have checked the help before. Actually my problem is that I expect Maple to perform such straigthforward conversions automatically,

Thanks for your answers. The help page of evalm is absolutely misleading for me.

I just wanted to perform some abstract manipulation on Matrices (or other objects). One of the examples shows a simple one.

restart;

evalm((A &* B) &* (2*B)-B &* Id);

                               /      2\      
                             2 \A &* B / - B Id

Without evalm how can I perform this? (Ok,  it is a very limited capability).
 

simplify((A &* B) &* (2*B)-B &* Id);
 

It doesn't work.
 

Thanks for your answers. The help page of evalm is absolutely misleading for me.

I just wanted to perform some abstract manipulation on Matrices (or other objects). One of the examples shows a simple one.

restart;

evalm((A &* B) &* (2*B)-B &* Id);

                               /      2\      
                             2 \A &* B / - B Id

Without evalm how can I perform this? (Ok,  it is a very limited capability).
 

simplify((A &* B) &* (2*B)-B &* Id);
 

It doesn't work.
 

Thanks for your idea. Of course, it works in Maple 12 too.

Thanks for your idea. Of course, it works in Maple 12 too.

Thanks for the idea. I have a lot of library path definitons in my maple.ini, After deleting them the example works.

I don't know which is the problematic.