Generation is related to Family. Family is related to Grandfather. Grandfather is a different concept from Grandmother. Grandmother is related to Relative. 
Myth is a synonym of Legend. Legend is a type of Book. Method is a type of Book. 
Generation <--RelatedTo--> Family <--RelatedTo--> Grandfather <--DistinctFrom--> Grandmother <--RelatedTo--> Relative 
Myth <--Synonym--> Legend --IsA--> Book <--IsA-- Method 