123,729 reputation
8117240
bio website von-eitzen.de/math/tntrep.xml
location Bonn, Germany
age 49
visits member for 2 years, 3 months
seen 8 hours ago

I did study math and had a knack for it, but I am sooo out of that business now ...


Feb
6
answered Prove by induction $a-b|a^{n}-b^{n}$ for $n\in\mathbb N$
Feb
6
answered proving something is not a well formed formula
Feb
6
comment proving something is not a well formed formula
I tried to format the question towards legibility, but I'm not sure what to make of the last part. Also, what can be said about the $A_i$?
Feb
6
revised proving something is not a well formed formula
added 62 characters in body
Feb
6
comment Sum of digits in Fibonacci sequence
More precisely, you don't obtain the remainder if $n>0$ is a multiple of $9$, inwhich case you obtain $9$ instead of $0$. But that doesn't destroy the (eventual) periodicity.
Feb
6
comment Show that for all natural $a$, $2008\mid a^{251}-a$.
@CalvinLin $(a,8)=1$ suffices.
Feb
6
answered Show that for all natural $a$, $2008\mid a^{251}-a$.
Feb
6
answered Finding radius of the central radius?
Feb
6
answered Differentiating a product symbol
Feb
6
answered Unique set of inference rules for a deductive system?
Feb
6
answered Is it true in general that a filter is given by the intersection of the ultrafilters refining it?
Feb
6
comment Showing that the integral of $x^nf(x)=0$ where $f$ is Lebesgue Integrable.
What limit is supposd to be $0$? The expression does not depend on $n$. Also, your title speaks of an integral equalling $0$??
Feb
6
comment Rewrite set theory formal
It looks like half your $:$ should be $\to $.
Feb
6
comment Bourbaki on the fact that continuous function on a compact is uniformly continuous
Btw, shouldn't $X$ be a uniform space as well? In other words: I don't recall if compact needs Hausdorff or not in Bourbaki
Feb
5
comment Bourbaki on the fact that continuous function on a compact is uniformly continuous
Do yo understand the usual proof for metric space $X'$? The formulation with uniform spaces and entourages is mostly jsut a "translation".
Feb
5
comment Is this a linear relationship and is this equation valid?
Don't be confued just because the "cause" bouquet number gets eliminated! Functions are only cum hoc, not necessarily propter hoc, so to speak.
Feb
5
comment Big O notation - Proving that a function is not O(n)
What is 4n2? $4n^2$?
Feb
5
reviewed Close What is the basis and rank of matrix in linear algebra?
Feb
5
answered The period of the function $f(x)=a\cdot \sin(ax)+a$
Feb
5
answered Notation for a subset of a powerset