Let is a type of Leave. Let is related to Permission. Permission is a type of Approval. Approval is derived from Approve. 
Liability is related to Company. Company is related to Similar. Similar is related to Trade. Trade is related to Action. 
Leave <--IsA-- Let <--RelatedTo--> Permission --IsA--> Approval --DerivedFrom--> Approve 
Liability <--RelatedTo--> Company <--RelatedTo--> Similar <--RelatedTo--> Trade <--RelatedTo--> Action 