Bartlett continued to search deeper to find a way to establish the notation from first principles. After some initial mis-steps, he discovered a new notation for the second derivative which can be used literally and does not require special formulas to manipulate. Additionally, when using the new notation, Bartlett was able to infer a new formula for relating different derivatives.
— Read on www.tulsatoday.com/2019/04/11/tulsa-teacher-discovers-flaw-in-calculus/
Cool shit yo!