in this In poset ‘A’ maximal element set (yes it is a set) contains just a single element which is ‘a’ means it is the maximum/greatest element. Similarly,minimal element set contains just a single element which is ‘d’ means it is the minimum/least element ”
now come to the poset B which contain minimal elements { e f } and maximal elements { a b } in this elemets of maximal set and elements of minimal set belongs to the antichain ( any two distict element are incomaparable / no edge between them …..
poset C mimimal elements { c h d }
maximal elements { a f }
poset D minimal elements { e d }
maximal elements { a b }
( their is diffrenece between “ maximum and miximal elemets “ & “ minimum and minimal element “ if their is only one minimal element in that case it is minimum and if their is only one maximal element than it is maximum..)
if their any mistake please notify me …...thanks