For 10 points, identify this letter which is used to denote electromagnetic radiation whose wavelength is shorter than X rays.
The Erlang distribution is a special case of a distribution named for this letter, and has free parameters alpha and theta, while in special relativity, it represents the quantity one over square root of one minus beta squared, or the Lorentz factor. This letter is sometimes used to denote the Euler-Mascheroni constant, and the function denoted by this extends the factorial to real and complex numbers. For 10 points, identify this letter which is used to denote electromagnetic radiation whose wavelength is shorter than X rays.
The Erlang distribution is a special case of a distribution named for this letter, and has free parameters alpha and theta, while in special relativity, it represents the quantity one over square root of one minus beta squared, or the Lorentz factor.
{gamma}