Notes of Omission

“It’s obvious from the above how…”

“From this, it follows immediately that…”

“Clearly, this is an example of…”

The inferences made in statements like these are almost never obvious, immediate, or clear. For the nomadic layperson, they become trail markers that tell you exactly where the experts are taking shortcuts. And they take many.

I guess they expect us to catch up to them later 😅


We said that the identities, symmetries, and composition rule in FinSet “are obvious.” In math lingo, this just means “we trust that the reader can figure them out, if she spends the time tracking down the definitions and fitting
them together.”

An Invitation to Applied Category Theory, Seven Sketches in Compositionality. Brendan Fong, David I. Spivak. (July 2019)


Somehow it’s obvious that…” – David Spivak

Gotta love watching an expert stumble momentarily while trying to figure out just why something is supposedly obvious.

I mean, if you gotta try that hard… 😂

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