Although he never published this work in his lifetime, he developed many different approaches to the topic with many different notations being tried out to find the one which was most useful.
Kahit na siya ay hindi nai-publish na ito gagana sa kanyang buhay, siya ay binuo ng maraming iba't-ibang pagtugon sa mga paksa na may maraming iba't-ibang notations na tried out upang mahanap ang isa na kung saan ay pinaka-kapaki-pakinabang.