
"""
≪(μ,ν)

# Absolute continuity

The following are equivalent:
1. μ ≪ ν
2. μ is absolutely continuous wrt ν
3. There exists a function f such that μ = ∫f dν
"""
function ≪ end

"""
≃(μ,ν)

# Equivalence of Measure

Measures μ and ν on the same space X are equivalent, written `μ ≃ ν`, if `μ ≪ ν` and `ν ≪ μ`.

Note that this is often written `~` in the literature, but this is overloaded in probabilistic programming, so we use alternate notation.
"""
function ≃(μ,ν)
return (μ≪ν && ν≪μ)
end
