Here is a quick cheat sheet of useful Unicode characters you can use in Jupyther Lab and Julia language:
Greek Alphabet
α \alpha
β \beta
γ \gamma
∇ \delta
ϵ \epsilon
ζ \zeta
η \eta
θ \theta
ι \iota
κ \kappa (should look like 'k')
λ \lambda
μ \mu
λ \lambda
μ \mu
ν nu (not supported in Jupyther)
ξ \xi
ο omnicron (not supported in Jupyther)
π \pi
ρ \rho
σ \sigma
τ \tau
υ upsilon (not supported in Jupyther)
ϕ \phi
χ \chi
ψ \psi
ω \omega
Hebrew
ℵ \aleph wiki
Machine Learning
x̂ x\hat
∑ \sum
± \pm (plus minus)
Math
∡ \measuredangle∑ \sum
± \pm (plus minus)
≠ \ne
≥ \ge (greater or equal)
≤ \le (less or equal)
⌀ \diameter
0° 0\degree
⌀ \diameter
0° 0\degree
Sets
∈ \in
Logic
∴ \therefore⊻ \xor