
Boltzmann Factor
Any term of the form e^{/τ} is called a Boltzmann Factor.

Gibbs Factor
Any term of the form e^{(Nμ)/τ} is called a Gibbs factor.

Gibbs Sum
The Gibbs Sum is the sum of all of the Gibbs Factors for the states and numbers of a system, and is given by:
Z_{G}(μ, τ) = e^{(Nμ)/τ} 
Partition Function
The Partition Function represents the sum of all of the Boltzmann Factors for the states of a system, and is given by:
Z = e^{/τ} 
Planck distribution function
The Planck distribution function describes the average number of photons < s > in a particular frequency σ for blackbody radiation and is given by:
< s > = 
StefanBoltzmann law of radiation
The StefanBoltzmann law of radiation gives the energy density of radiation in a cavity, as can be expressed:
= τ^{4}
Terms
Formulae
The probability of finding a system in energy state if the system is in thermal contact with a reservoir 
P() =

The entropy of blackbody radiation 
σ = ()^{3}
