Narrow is a synonym of Tight. Tighten is etymologically related to Tight. Tighten is related to Twist. 
Math is related to Solution. Solution is a type of Statement. 
Narrow <--Synonym--> Tight <--EtymologicallyRelatedTo-- Tighten <--RelatedTo--> Twist 
Math <--RelatedTo--> Solution --IsA--> Statement 