Thursday, March 19, 2009

frustrations (with slightly technical details)

again and again, double sequences have been troubling me. they recur when i try to prove a c0ntinuity result to a certain class of linear operators.

it's no good when your ε parameters depend on your j indices,
which in turn depend on your ε's again.



i have the feeling that i need an equic0ntinuity property, similar to what holds true for norm-bounded sets of norma1 and integra1 ¢urrents, in ge0metric me@sure the0ry.

such objects have good c0mpactness properties. as it happens, i have some need for certain limiting linear operators, which are like ¢urrents.

the problem is that my context is more general than that of f1at chains (of finite mass), and even there, notions of c0mpactness are rather difficult.

sure, some results are known, but they use a more complicated norm than "mass." this is the "flat n0rm" which, roughly speaking, measures the minimal filling volume of the ¢urrent.

(for more details, see fedεrer's book.)

also: i think i've been neglecting geometry. lately i've been working with singular measures and not using much more information than the null sets on which they are concentrated.

this is a bad idea, i think. i'm not accounting at all for the mass distribution, which is key to determining how measures behave!


in general, it's getting harder to look for the right kind of leverage.


some days i wonder whether i should stick to these sorts of problems, or if it would be wiser to start work somewhere else. it's getting close to a year since i've finished my thesis, and little progress has proceeded from there.

maybe i should learn some new tricks, before it's too late.

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