Tagged Questions
1
vote
1answer
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whats the order of a distributional derivate?
I have to calculate the derivatives of order $\le 2$ of for example $f(x) = |x|$, is it the same as the second derivate, what does this "of order $\le 2$" mean? calculating distributionell derivatives ...
9
votes
1answer
232 views
Origin of the name 'test functions'
This is a very simple question really: where did the name 'test functions', used nowadays when speaking of infinitely differentiable and compactly supported functions, come from? More to the point: is ...
8
votes
1answer
248 views
What is the name for the archetypical example of a test function, $\varphi(x)=e^{1/(x^2-1)}$?
$$
\varphi(x)=e^{1/(x^2-1)}
$$
This function (on the interval $\quad]\!-1,1[ \,\,\, $, outside of it simply $\equiv0$) is used as the typical example of a test function / bump function, I have so ...
