▁a ▁two - variable ▁polynomial ▁from ▁which ▁either ▁the ▁chrom atic ▁polynomial ▁or ▁the ▁flow - pol ynomial ▁could ▁be ▁obtained ▁by ▁setting ▁one ▁of ▁the ▁variables ▁equal ▁to ▁zero , ▁and ▁adjust ing ▁signs .” ▁T ut te ▁called ▁this ▁function ▁the ▁dich rom ate , ▁as ▁he ▁saw ▁it ▁as ▁a ▁general ization ▁of ▁the ▁chrom atic ▁polynomial ▁to ▁two ▁variables , ▁but ▁it ▁is ▁usually ▁referred ▁to ▁as ▁the ▁T ut te ▁polynomial . ▁ ▁In ▁T ut te ’ s ▁words , ▁“ This ▁may ▁be ▁unf air ▁to ▁Hass ler ▁Whit ney ▁who ▁knew ▁and ▁used ▁analog ous ▁coefficients ▁without ▁bother ing ▁to ▁aff ix ▁them ▁to ▁two ▁variables .” ▁( There ▁is ▁“ not able ▁confusion ” ▁about ▁the ▁terms ▁dich rom ate ▁and ▁dich rom atic ▁polynomial , ▁introduced ▁by ▁T ut te ▁in ▁different ▁paper , ▁and ▁which ▁differ ▁only ▁slightly .) ▁The ▁general isation ▁of ▁the ▁T ut te ▁polynomial ▁to ▁mat roid s ▁was ▁first ▁published ▁by ▁Cra po , ▁though ▁it ▁appears ▁already ▁in ▁T ut te ’ s ▁th esis . ▁ ▁Independ ently ▁of ▁the ▁work ▁in ▁algebraic ▁graph ▁theory , ▁Pot ts ▁began ▁studying ▁the ▁partition ▁function ▁of ▁certain ▁models ▁in ▁statistical ▁mechan ics ▁in ▁ 1 9 5 2 . ▁The ▁work ▁by ▁Fort u in ▁and ▁K aste le yn ▁on ▁the ▁random ▁cluster ▁model , ▁a ▁general isation ▁of ▁the ▁Pot ts ▁model , ▁provided ▁a ▁un ifying ▁expression ▁that ▁showed ▁the ▁relation ▁to ▁the ▁T