Can anyone offer a solution (or hint) to exercise 2.1 of Misner,Thorne, Wheeler - "Gravitation", stating:
"Show that equation p⋅v=⟨˜p,v⟩ is in accord with the quantum-mechanical properties of a de Broglie wave, ψ=eiϕ=exp[i(k⋅x−ωt)]"
p stands for the momentum vector
˜p stands for "momentum 1-form"
v is any vector
Thank you for your help.