▁be ▁written ▁as ▁. ▁ ▁Re fin ement ▁types ▁are ▁thus ▁related ▁to ▁behavior al ▁sub ty ping . ▁ ▁History ▁ ▁The ▁concept ▁of ▁ref in ement ▁types ▁was ▁first ▁introduced ▁in ▁Fre eman ▁and ▁Pf en ning ' s ▁ 1 9 9 1 ▁Re fin ement ▁types ▁for ▁ML ▁, ▁which ▁presents ▁a ▁type ▁system ▁for ▁a ▁subset ▁of ▁Standard ▁ML . ▁The ▁type ▁system ▁" pres erves ▁the ▁decid ability ▁of ▁ML ' s ▁type ▁inference " ▁whilst ▁still ▁" allow ing ▁more ▁errors ▁to ▁be ▁detected ▁at ▁compile - time ". ▁In ▁more ▁recent ▁times , ▁ref in ement ▁type ▁systems ▁have ▁been ▁developed ▁for ▁languages ▁such ▁as ▁H askell , ▁Flow , ▁Type Script ▁and ▁Scala . ▁ ▁See ▁also ▁▁ ▁Li qu id ▁H askell ▁ ▁Dep endent ▁types ▁ ▁References ▁ ▁Category : Type ▁theory ▁Category : Type ▁systems <0x0A> </s> ▁Helen ▁Kath le en ▁Court ney ▁( 5 ▁June ▁ 1 9 5 2 ▁– ▁ 4 ▁March ▁ 2 0 2 0 ) ▁was ▁a ▁New ▁Zealand ▁cart oon ist ▁and ▁illustr ator , ▁known ▁for ▁her ▁work ▁on ▁Bro ads heet . ▁ ▁Life ▁ ▁Of ▁Ng ā ti ▁To a ▁Rang ati ra , ▁Ng ā ti ▁R au ka wa ▁ki ▁te ▁T ong a ▁and ▁Te ▁ Ā ti ▁A wa ▁descent , ▁Court ney ▁grew ▁up ▁in ▁West ▁A uck land . ▁ ▁Career ▁ ▁Court ney ▁joined ▁the ▁Bro ads heet ▁collect ive ▁in ▁ 1 9