why software used by the Physics Derivation Graph is open source

The Physics Derivation Graph content is available under the Creative Commons Attribution 4.0 International License, and I use open source software.

• Python license
• LaTeX
• graphviz license
• OCaml license
• SymPy license
• Sage

I avoid software that is not open source and not free

• Matlab
• Mathematica
• Maple
• Magma
• MathCAD

My motivations for this include

• wider accessibility of the results due to fewer constraints
• enable other people to build on top of the results
• contribute back to the community which has provided so much