It is important to emphasise that, among the various choices for 𝜆jk and Aⁱᵃ_(jb), some are intrinsic to the differential structure of the manifold ℳ. In other words, among all the operators of D-differentiation, some arise from the differential structure of ℳ. […] On the other hand, there exist operators of D-differentiation that do not follow from the differential structure of ℳ.

And also, many of the problems I’d had with what seemed to me to be — I don’t know what you’d call it — the angels-dancing-on-the-head-of-a-pin aspect…

Many insects probably use this strategy, which is a close analogy to crypsis in the visible world—camouflage and other methods for blending into one’s visual background.

Another use of music in the extradiegetic space is with the bumper (sometimes called an eyecatch or just a bump), which is a brief text occurring during commercial breaks in the middle of a program.