The arrows between the gerund/present participle `` SITTING '' and the nouns `` agent '' and `` location '' express the diagram 's basic relationship ; `` agent is SITTING on location '' ; `` Elsie '' is an instance of `` CAT '' .
The arrows between the gerund `` SITTING '' and the nouns `` agent '' and `` location '' express the diagram 's basic relationship ; `` agent is SITTING on location '' ; `` Elsie '' is an instance of `` CAT '' .