... common divisor
- iterated summation and product operators
- differentiation and integration
High flexibility:
- user defined constants and arguments, both free - and dependent on other arguments + possibility of use in functions
- user defined functions (both free and depended)
- user defined recursive arguments + simple (controlled) recursion (1 recursive argument)
- user defined recursive functions / expressions (any) - complex, many arguments, no limitation
- internal syntax checkin