I recommend this be crossposted to sage-devel and perhaps to sage-combinat
There are people who know all about formal power series in Sage...


On Tuesday, August 16, 2016 at 9:25:08 AM UTC+1, Martin R wrote:
>
> Hi Waldek!  (and all others of course, too!)
>
> Am Samstag, 13. August 2016 22:08:16 UTC+2 schrieb Waldek Hebisch:
>
> Well, Sage uses Maxima as its default integrator.  There are whole 
>> classes of functions that FriCAS can integrate and Maxima can not 
>> (the opposite happens, but is rare).  Also, it is not hard 
>> to find examples where Maxima gives nonelemetary answer when 
>> elementary integral exists.  FriCAS answers are irredundant: 
>> nonelementary parts are necessary to express the answer. 
>
>
> integration is one (and so far the only) part of sage which actually uses 
> FriCAS (optionally).
>  
>
>> FriCAS has solver for differential linear ODE-s of higher 
>> order and for systems.  IIUC Sage (via Maxima) is limited to 
>> order 2. 
>>
>
> Great, I added an example from one of the input files.  (I know nothing 
> hardly anything about ODE's.)
>
> I belive that FriCAS limit command is stronger than Maxima 
>> and Sympy.  The difference here is probably smaller than in 
>> case of integrator, but still there is reason to call 
>> FriCAS limit. 
>>
>
> OK, I'll check!
>  
>
>> I wonder if Sage has symbolic Jordan decomposition?  FriCAS 
>> has (under name generalizedEigenvectors).
>
>
> I don't know what you mean here.  Sage has Jordan decomposition over 
> algebraic numbers.
>
> I checked generalizedEigenvectors matrix [[1, x], [0, 1]] but this gives a 
> wrong result:
>
> (5) -> m := matrix([[1,x],[0,1]])
>
>         +1  x+
>    (5)  |    |
>         +0  1+
>                                             Type: 
> Matrix(Polynomial(Integer))
> (6) -> generalizedEigenvectors m
>
>                                 +0+ +1+
>    (6)  [[eigval= 1,geneigvec= [| |,| |]]]
>                                 +1+ +0+
> Type: List(Record(eigval: 
> Union(Fraction(Polynomial(Integer)),SuchThat(Symbol,Polynomial(Integer))),geneigvec:
>  
> List(Matrix(Fraction(Polynomial(Integer))))))
>  
>
>> Given activity 
>> of combinat group Sage probably has support for formal 
>> power series.  But I wonder how it compares to FriCAS 
>> support? 
>>
>
> This is another area where FriCAS is far ahead of sage, especially 
> concerning expansion of expressions. 
>
> FriCAS has various noncommutative stuff.  IIUC physicists 
>> are interested in shuffle and related algebras and computation 
>> in them is related to Hall bases.  While we do not have 
>> ready shuffle algebra needed ingerdients are present in 
>> FriCAS.
>
>
> I think the only way to compete with sage in the territory of algebras is 
> speed.  In particular, the shuffle algebra is in  sage and its quite easy 
> to add new algebras.
>  
>
>> As a little curiosity, from 2011 we have domain for ordinals. 
>> At ISSAC 2015 support for ordinals was prominently present 
>> among new things freshly added to Maple.  I guess here 
>> FriCAS is ahead of Maple and Maple is ahead of Sage. 
>>
>> OK, that's another area I know nothing about and which apparently sage 
> doesn't have.
>
> Thanks for your support!  Besides, the interface is now mostly ready!
>
> Martin
>

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