The last chapter of the book "Fundamentals of Quantum Optics and Quantum Information" by Peter Lambropoulos and David Petrosyan has information about this.
Homework Statement
Let f be a distribution on R and suppose that its kth derivative is 0. Prove that f is a polynomial.
2. The attempt at a solution
I honestly haven't a clue how to start. If I could treat f like a "regular" function, this would so easy.
That's what many books say too, but I don't see how it immediately follows. For example, I don't see how it rules out that three subsimplices can share a common facet.
First, some definitions:
An n-simplex is defined as the convex hull of n+1 affinely independent vectors in Rd (its vertices). A face of a simplex is defined to be the convex hull of any subset of its vertices. A facet of a n-simplex is a face that is an (n-1)-simplex. A triangulation T of an...
There are no constraints on an. I do know of a couple that might shed some light on this general situation. As you previously mentioned, if the an are all 0 (or are eventually all 0), then the limit exists for all n. If the an are eventually all some nonzero constant, then we know the limit...
Homework Statement
Let an be a sequence of real numbers. For what values of x does lim anxn exist?
The attempt at a solution
Let us suppose that lim anxn exist and is equal to b. What can we say about x? Hmm...there is a monotonic subsequence that converges to b, say a_{k_n}x^{k_n}. If...
Homework Statement
Prove lim na^n = 0 when 0 < a < 1.
The attempt at a solution
Without danger, we change from the discrete n to the continuous x so that now we have to prove that lim xa^x = 0. Let e > 0. We have to find an N such that xa^x < e for all x > N. Now if xa^x < e is the same as...