Edgeworth series
The Gram–Charlier A series ( named in honor of Jørgen Pedersen Gram and Carl Charlier ) , and the Edgeworth series ( named in honor of Francis Ysidro Edgeworth ) are series that approximate a probability distribution in terms of its cumulants . 
<triplet> Edgeworth series <subj> Francis Ysidro Edgeworth <obj> named after