I am currently using Sympy.

The problem is that it was developed in Python.

An alternative is pkg SymEngine, which was developed in C ++.

My doubt is: is there a better Pkg than Sympy and SymEngine?

I use Nemo : https://nemocas.org/ This is a CAS (Computer Algebra System), not a â€śsymbolic maths packageâ€ť, but for *my* computations itâ€™s always perfect.

ModelingToolkit.jl is the most similar right now in pure Julia. The CAS portions of it are being pulled out to a Symbolics.jl specifically for the CAS, but if you want to use it today a lot (but not all, not at all) is shown in the tutorial: Symbolic Calculations and Building Fast Parallel Functions Â· ModelingToolkit.jl. It basically adds to SymbolicUtils.jl a bunch of stuff like differentiation, function building (â€ślambdifyâ€ť), sparsity handling, function registering, etc. It has more than SymEngine and less than SymPy (in terms of a CAS. For symbolic-numerics it has a ton of unique stuff)

Reduce.jl and/or ModelingToolkit.jl may be places of interest for you.

I am currently using Sympy.

The problem is that it was developed in Python.

The fact that itâ€™s Python is not the problem. Maybe itâ€™s slow, but itâ€™s also quite feature rich. You may not necessarily find everything you need in other Julia or C++ packagesâ€¦

Symbolics.jl is now released: [ANN] Symbolics.jl: A Modern Computer Algebra System for a Modern Language