Fundamental is a type of Factor. Fundamental is related to Theory. Theory is a synonym of Scheme. Scheme is a synonym of Imagine. 
Couple is a synonym of Item. Item is related to Property. 
Factor <--IsA-- Fundamental <--RelatedTo--> Theory <--Synonym--> Scheme <--Synonym--> Imagine 
Couple <--Synonym--> Item <--RelatedTo--> Property 