• 
New option in Setup: redefinesum, so that the sum command is redefined in such a way that a) the sum arguments are processed in a way avoiding premature evaluation and related unexpected results or error interruptions b) the sum command includes new functionality present in Physics:Library:Add to perform sum over integer values of many indices, as in

or
> 


(1.1) 
New option: redefine sum so that its arguments are processed by the more modern Physics:Library:Add and so that it can perform multiindice summation.
Example:
By default, the sum command is not redefined, so the value of redefinesum is
> 


(1.2) 
Consider this multiindex summation functionality of the Physics:Library:Add command
> 


(1.3) 
For instance, for n = 2,
> 


(1.4) 
This functionality can be plugged directly into the sum command. For that purpose, set redefinesum to true
> 


(1.5) 
You can now compute directly with sum. The lefthand side is inert while the righthand side is computed
> 


(1.6) 
> 


(1.7) 
> 


(1.8) 
The formula for the integer power of a sum
> 


(1.9) 
> 


(1.10) 
> 


(1.11) 
Verify whether this equation is true
> 


(1.12) 
Besides this new functionality, the redefined sum does a more modern handling of its arguments, consider a typical problem posted in Maple primes
> 


(1.13) 
In the following summation, j is a dummy summation index, so the value just assigned, , is not expected to interfer with the summation. This is the case with the redefined sum
> 


(1.14) 
while without redefining sum the input above is interrupted with an error message. Likely, in this other case also reported in Mapleprimes
> 


(1.15) 
the following two summations can be performed after having redefining sum:
> 


(1.16) 
For the summation above, without redefining sum, it returns 0 instead of unevaluated, because of a premature evaluation of the function with an unassigned index i before performing the summation. Returning unevaluated as (1.16) permits evaluate the sum at a latter moment, for instance attributing a value to f
> 


(1.17) 
And this other sum where f is given from the begining also returns 0 without redefining sum
> 


(1.18) 
Problems like this other one reported in Mapleprimes here also get resolved with this redefinition of sum.
