On Jun 18, 4:53 pm, quasi <qu...@null.set> wrote: > > It looks to me like Luttgens is using the phrase > > "mutatis mutandi" > > as a form of reasoning.
He is using it,like everyone else who uses it, as a phrase that introduces the next claim in his argument, akin to "clearly" or "similarly", nothing more.
If I describe a new algorithm I invent, not in general terms, but with, say, n fixed at 3, and then say "there is nothing special about n = 3 here, the algorithm applies, mutatis mutandis, to any positive integer", the only things that are required for my description to be acceptable are that the reader knows exactly what changes are necessary to adjust the algorithm to the general case and that the resulting algorithm remains correct. The phrase occurs in proofs and examples in contexts similar to the hypothetical one I sketched out here. British scholars of an earlier generation were especially fond of it.
> Hence my response that (whatever it is) it's certainly not > a valid principle of mathematical reasoning.
Since it is not even a complete sentence, it is obvious that it cannot be a principle or an axiom or a theorem. And the value of your response in helping the writer see what is missing in his argument is nil.