when Death smiles upon you ..

My god. I am so f*cking stupid, but I mean that in a good way.

If it clarifies the situation, I'm laughing at myself .. half-hysterically and half-nervously, of course. But regardless of context, it is laughter.

It took me "far too long" [1] to realise that a particular claim follows ..

.. not from a big theorem, a moderate proposition, or even a simple lemma. It follows from a change of variable, via integration. That's all.

Well, that's embarrassing, but I suppose I should take the advice I've always given my students:

one stupid mistake now means one less stupid mistake later [2].

All righty. Back to work, then.

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[1] .. and no, I'm not going to define that precisely. I am embarrassed for a good reason, you know.

[2] The advice was meant to be reassuring, for when my students do poorly on the quizzes I give them.