OpenAxiom does not support unicode symbols like greek letters, math symbols, letterlike symbols, as well as sub- and superscripts.
OpenAxiom should support unicode input, so that the user is able to create alias names.
Examples for possible Aliases:
σ = sigma
ς = varSigma
ρ = ChargeDensity
ℝ = Real;
≤ = '<='
This basically does not need any changes on how the compiler works, but simply which letters the system accepts.