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 Apr8 revised what's the difference between a rational number and an irrational number? added 1 character in body Apr8 comment what's the difference between a rational number and an irrational number? @gideon Well thanks, especially since this caused me to look back at the answer and correct an error. Mar7 comment Complex distributions - what are the appropriate test functions? @StephenMontgomery-Smith I wouldn't be surprised in the least, but I'd prefer to defer final judgement until I can be a bit more certain there's a mistake. Perhaps someone more familiar with CFT will someday have something definitive to say about this. Mar7 comment Complex distributions - what are the appropriate test functions? @StephenMontgomery-Smith Yeah I'm strongly inclined to agree -- I have never heard of analytic test functions either. Nonetheless, the calculation I wrote down appears in at least the most well-known, standard conformal field theory text, so I'd like to make sense of it somehow. Mar6 asked Complex distributions - what are the appropriate test functions? Feb20 comment Proving that a family of functions limits to the Dirac delta. +1: This is great, thank you. I'm still hoping, however, that someone will be able to tell me how to make the approach that uses complex analysis work as a matter of interest. Feb20 revised Proving that a family of functions limits to the Dirac delta. added 92 characters in body Feb19 asked Proving that a family of functions limits to the Dirac delta. Jan19 awarded Yearling Dec8 awarded Caucus Nov19 comment Pure Point Spectrum implies Spanning Eigenfunctions I think this would more appropriately be asked on math.SE. Nov2 comment Gradient of a function with base vectors Isn't this more appropriate for math.SE? Oct20 revised Big O notation for complex-valued functions of a real variable edited body Oct19 comment What is the dimension of the vector space of functions $f:\mathbb R\to\mathbb R$? Wonderful! Thanks Asaf. Oct19 accepted What is the dimension of the vector space of functions $f:\mathbb R\to\mathbb R$? Oct19 comment What is the dimension of the vector space of functions $f:\mathbb R\to\mathbb R$? Wow ok $2^{2^{\aleph_0}}$ it is then. Pretty monstrous (to a non-set-theory aficionado at least). That's a very nice last equation you wrote. Does it have a special name? Where in standard books would I find such wonderful gems? Oct19 asked What is the dimension of the vector space of functions $f:\mathbb R\to\mathbb R$? Sep27 comment How are eigenvectors/eigenvalues and differential equations connected? Great answer btw. Would you happen to know of any good references that treat ODEs heavily using linear-algebraic language as in this answer? In particular, a text which discusses Jordan normal form in this context as you allude to would be useful. I'll be teaching a math methods for physics class, and I'd find such a reference very useful. Sep23 comment How are eigenvectors/eigenvalues and differential equations connected? Shouldn't $e^{\lambda y}$ read something like $e^{\lambda t}$ instead? Sep10 awarded Revival