Person wants (to) Science. Mathematics is a type of Science. Mathematics is related to Study. Study is related to Physician. 
Separation is related to Split. Split is a type of Bottle. Drinking requires Bottle. 
Person --Desires--> Science <--IsA-- Mathematics <--RelatedTo--> Study <--RelatedTo--> Physician 
Separation <--RelatedTo--> Split --IsA--> Bottle <--HasPrerequisite-- Drinking 