I am writing an introduction to a mathematical text and have to convey the authorship of certain ideas and theorems. However, I am unsure which of the phrases I wanted to use are actually proper English. Let's say I have an author named Steven Stevenson; which of the following constructions would you use?
"Concept A is closely related to concept B via the trace formula of Stevenson's." or rather "Concept A is closely related to concept B via Stevenson's trace formula."?
"We present an algorithm based on an idea of Stevenson's." or rather "We present an algorithm based on an idea by Stevenson."?
"We employ this method together with an algorithm of Steven Stevenson's to construct something." or rather "We employ this method together with an algorithm by Steven Stevenson to construct something."?
Note that I am inclined to use the post genitive since these authors usually have several algorithms, ideas or theorems to their name.