Class is a synonym of Course. Course is related to Lecture. 
Mobile is related to Text. you are likely to find Text in/at/on Library. Library is related to Home. you are likely to find Vessel in/at/on Home. 
Class <--Synonym--> Course <--RelatedTo--> Lecture 
Mobile <--RelatedTo--> Text --AtLocation--> Library <--RelatedTo--> Home <--AtLocation-- Vessel 