I have not watched the talk in-depth so I can't tell whether it's trolling, but I have worked with academic CS papers. I would agree with an attempt to develop

I have not watched the talk in-depth so I can't tell whether it's trolling, but I have worked with academic CS papers. I would agree with an attempt to develop a new symbolism for describing CS theory, that was closer to modern programming languages, or at least to a LISP-like Domain Specific Language. It's true that the language of mathematics was optimized for a different medium: written formulas on paper. Algorithms are better expressed in pseudo-code, but to describe the exact effects of a language instructions we have to resort to formal semantics (whether denotational, operational or axiomatic), which basically describe the workings of a virtual machine in terms of a temporal logic expressed with mathematical symbols. The ellipsis in maths is usually an ambiguous symbol whose meaning changes depending on context. In CS, it typically represents either vectors in memory or successive recursive calls. Trying to provide a precise meaning for its usage is a legitimate endeavor; it appears that Steele is using symbols from vector maths to achieve it. What I get from skimming the video is that the combination of overlines and underlines would be a way to represent how you would combine your nested loops in imperative programming to traverse the data structure.