24
votes
3answers
1k views
the following inequality is true,but I can’t prove it
The inequality is
\begin{equation*}
\sum_{k=1}^{2d}\left(1-\frac{1}{2d+2-k}\right)\frac{d^k}{k!}>e^d\left(1-\frac{1}{d}\right)
\end{equation*}
for all integer $d\geq 1$. I use com …
2
votes
3answers
1k views
Why Does Induction Prove Multiplication is Commutative?
Andrew Boucher's General Arithmetic (GA2) is a weak sub-theory of second order Peano Axioms (PA2). GA has second order induction and a single successor axiom:
$$\forall x \forall …
4
votes
1answer
151 views
ERA, PRA, PA, transfinite induction and equivalences
I'm quite sure I don't understand very well the links between proof theoretical ordinals of theories, the axioms of transfinite induction and the objects a theory can prove to exis …
6
votes
4answers
640 views
Examples of “exotic” induction
Next week I am going to teach two lessons on induction to very motivated students from high schools. At some point I would like to talk about ordered sets, well-ordered sets, and m …
5
votes
2answers
245 views
Homotopy Transfer Theorem for Differential Graded Associative Algebras
As in Algebra+Homotopy=Operad by Bruno Vallette, let $A$ with multiplication $\nu$ be a differential graded associative algebra equipped with degree +1 map $h$ and let $H$ be a cha …
1
vote
1answer
172 views
experimental mathematics— how are floating point equations discovered/converted to exact equations
the 2005 AMS article/survey on experimental mathematics[1] by Bailey/Borwein mentions many remarkable successes in the field including new formulas for $\pi$ that were discovered v …
0
votes
0answers
230 views
Introduction to proofs: what is the best technique to use? [closed]
I just received my first assignment for a mathematical proofs course I am taking this year. We just began the course, and we have so far only covered examples of proofs (how to pro …
1
vote
0answers
55 views
Coinduction and corestriction are quasi-inverse equivalences for comodules?
I'm reading http://arxiv.org/abs/math/0310337.
There the following statement is given without proof:
Let $k$ be a field. Let $C$ be a counitary coaugmented coalgebra, i.e. there i …
0
votes
1answer
351 views
Maximum sum of 3 consecutive numbers in a permutation [closed]
Given that $X = \{0, 1, 2, ..., 7, 8, 9\}$, and $P$ is a permutation on $X$. Let $M(P)$ be the maximum sum of 3 consecutive elements. For example, if $P = (0, 2, 4, 1, 5, 7, 9, 3, …
7
votes
9answers
3k views
Is PA consistent? do we know it?
1) (By Goedel's) One can not prove, in PA, a formula that can be interpreted to express the consistency of PA. (Hopefully I said it right. Specialists correct me, please).
2) There …
26
votes
4answers
2k views
A principle of mathematical induction for partially ordered sets with infima?
Recently I learned that there is a useful analogue of mathematical induction over $\mathbb{R}$ (more precisely, over intervals of the form $[a,\infty)$ or $[a,b]$). It turns out t …
8
votes
2answers
376 views
Order statistics (e.g., minimum) of infinite collection of chi-square variates?
Hi everyone,
This is my first time here, so please let me know if I can clarify my question in any way (incl. formatting, tags, etc.). (And hopefully I can edit later!) I tried …
9
votes
3answers
635 views
Easier induction proofs by changing the parameter
When performing induction on say a graph $G=(V,E)$, one has many choices for the induction parameter (e.g. $|V|, |E|$, or $|V|+|E|$). Often, it does not matter what choice one mak …
6
votes
1answer
604 views
Symmetric Proof that Product is Well-Founded
This is a fairly minor, technical question, but I'll toss it out in case someone has a good idea on it.
Suppose $(X,<_X)$ and $(Y,<_Y)$ are well-founded orderings (not neces …
3
votes
1answer
232 views
For which classes of functions this inverse function formula gives a closed form expression?
Lets consider this method of finding inverse function:
$$f^{-1}(x) = \sum_{k=0}^\infty A_k(x) \frac{(x-f(x))^k}{k!}$$
where coefficients $A_k(x)$ recursively defined as
$$\begi …

