Ascending order date for each customer
Query Activity for ORDER BY xxx DESC LIMIT
Contraction of quotient ideal is quotient of contractions? I have been trying to solve this problem for quite a while. I am still unsure of whether any of the avenues I have pursued have been of any use. Any advice will be much appreciated. Question: Let $V$ be a finite-dimensional inner product space, and let $E$ be an idempotent linear operator on $V$. Prove that if $EE^* = E^*E$, then $E$ is self-adjoint. (This is essentially exercise 5(a) in sec. 80 on p.162 of Paul R. Halmos, Finite-Dimensional Vector Spaces, but Halmos didn't assume that the dimension of $V$ is finite.) Prove that $\liminf x_n = -\limsup (-x_n)$ How can we prove that $\liminf x_n = -\limsup (-x_n)$?  The definitions we are using are $\limsup x_n = \lim\limits_{n\to\infty} \sup\{x_k; k\ge n\}$ $\liminf x_n = \lim\limits_{n\to\infty} \inf\{x_k; k\ge n\}$ Citation colour with Beamer + Hyperref + Natbib I'm using natbib for citation with a custom bibstyle. I'm working on a presentation using LaTeX beamer and for some reason the citation marker doesn't have the colour that is specified to hyperref. The citation marker is black instead of green. I'll give you a MWE:    \documentclass{beamer} \hypersetup{   colorlinks,   citecolor=green,   linkcolor=red }  \usepackage{filecontents} \begin{filecontents}{mybib.bib} @ARTICLE{Bar2011,   author = {F. Foo and F. Bar},   title = {Foo and Bar},   journal = {Journal of Foo},   year = {2011},   volume = {1},   pages = {1--3} } \end{filecontents}  \usepackage[comma,numbers,sort&amp;compress]{natbib} \bibliographystyle{plain}  \begin{document} Dummy referefence to~\cite{Bar2011} \bibliography{mybib} \end{document}   For the purpose of the MWE I have selected the plain bibstyle, however, changing that to something else (including the custom style I want to use) doesn't affect the label colour.    Is there any patch for this problem? I am struggling to convert .dwg to .shp, ideas? Any ideas as to how can I convert dwg to shp?  I tried Kosmo and gvSIG. gvSIG kind of worked but it seems like I lost information.. in addition everything was converted into lines, no polygons. I can manually recreate the polygons, but there must be a better program to do this conversion.  Ideas? Let $(a_n)$ be a strictly increasing sequence of positive integers such that: $a_2 = 2$, $a_{mn} = a_m a_n$ for $m, n$ relatively prime. Let $(a_n)$ be a strictly increasing sequence of positive integers such   that: $a_2 = 2$ and $a_{mn} = a_m a_n$ for $m, n$ relatively prime. Show that $a_n = n$, for every positive integer $n$.   This is a result apparently due to Paul Erdős, and  has a proof by induction.  I tried like this, $a_{10}=a_2a_5$. After this what we can do?    [Editor's comment] Possibly due to the apparent simplicity of the conditions it may be difficult to appreciate the subtleties of this question. If we try and construct a counterexample like $a_3=4$, $a_4=5$, $a_5=6$, then the requirements dictate $a_6=8$, $a_{10}=12$, $a_{15}=24$. At this point we realize that we have been speeding. For monotonicity forces $a_9\le 11$, and therefore $a_{18}\le22&lt;a_{15}$, violating the requirements. It is not obvious why something similar ruins all the modifications to the sequence $a_n=n$. [/comment, JL] Here is an interesting piece of code that my fellow team members were just having a slightly heated discussion about...    Dim fred As Integer    If True Then fred = 5 : fred = 3 : fred = 6 Else fred = 4 : fred = 2 : fred = 1   After executing the above code snippet, what is the value of fred?  Try not to cheat and debug the code.  This is a highly contrived code example that started out as an example of using the colon with an If statement, but then someone decided to take it upon themselves to proffer a result for fred.  UPDATE: I would not normally write code like this and this snippet only serves as an example. As it so happens, this question originated from a discussion involving the creation of a coding standards document for our team. What is the norm of this bounded linear functional? Let $a$, $b$ be two arbitrary but fixed real numbers such that $a &lt; b$, let $C[a,b]$ denote the normed space of all continuous real (or complex) valued functions defined on $[a,b]$ with the maximum norm, and let $f$ be the functional defined on $C[a,b]$ as $$f(x):= \int_{a}^{b} x(t) x_0(t) dt $$ for all $x$ in $C[a,b]$, where $x_0$ is a fixed element of $C[a,b]$.   Now $f$ is evidently linear and bounded. How to compute the norm of $f$? What is this norm?   And what is the norm of the bounded linear functional $g$ defined as follows: $$g(x):= \int_{a}^{(a+b)/2} x(t) \cdot dt - \int_{(a+b)/2}^{b} x(t) \cdot dt$$ for all $x$ in $C[a,b]$? (How) Can I use existing stapled electrical wire to fish new wire? I nicked an electrical cable while doing a plumbing repair and so need to fix it. I previously  about repairing the damage in place, but there are receptacles 6-10 feet away on either side of the damaged wire, so it may not be too difficult to just pull new wire. Most of the wire is run horizontally through the studs, which is great, but it will at least be stapled at both boxes (and possibly more). The horizontal run is ~18" up from the floor, while the receptacles are ~6". There is also an inside corner the wire is run through. Wire is 12/2.  Is it possible to use the existing wire to fish the new wire, even though the existing wire is stapled? Would I need to open up the wall to remove the staples?  I found a , but that pertains to telephone wires which sometimes use different staples than electrical wires. Prove a differentiable function between banach spaces is continuous How is Leibniz's rule for the derivative of a product related to the binomial formula? Possible Duplicate:          The  describes the expansion of the $n$th power of the sum $(a+b)$:  $$(a+b)^n = \sum_{k = 0}^n {n\choose k}a^kb^{n-k}$$  In calculus, there is a generalization of the product rule called , which describes the expansion of the $n$th derivative of the product of two functions $f$ and $g$:  $$(fg)^{(n)} = \sum_{k = 0}^n {n\choose k}f^{(k)}g^{(n-k)}$$  It's not difficult to prove using the product rule and induction, what I'm really trying understand here is why the formula is true. Is there a way to prove it using the binomial formula? How are these two formulas related? Is there a combinatorial proof for Leibniz's rule like there is for the ?   I understand this question is a bit vague, but I hope you'll agree that these two formulas look so similar it just feels like there should be some relation between the two. Of course this is not necessarily true, but I'm hoping it's not just a crazy coincidence. Flying EU to UK to EU. Can I get duty free alcohol? On the 20 of March this year I will be flying from Ireland to the UK and then on the another EU country.  Can I buy duty free alcohol (as in alcohol with no tax) leaving the UK ? pip: AttributeError: 'module' object has no attribute 'SSL_ST_INIT' Inverse of a matrix is expressible as a polynomial? Let $A$ be an $n \times n$ matrix. Prove that if A is invertible, then there exists a polynomial $p$, such that $A^{-1}=p(A)$  Thus far:  Let $W$ denote the $k$ dimensional A-cyclic subspace spanned by a vector $v$.  Then, $I_n=\sum_{i=0}^{k} a_{i}A^i$ for some scalar $a_i$.  What I want to do is multiply both sides by $A^{-1}$, so that way it just falls into my hands, but Im not sure that is 'legal'. Is stage.*.example.com valid for a wildcard DNS CNAME? I have read lots of information about page caching and partial page caching in a MVC application. However, I would like to know how you would cache data.  In my scenario I will be using LINQ to Entities (entity framework). On the first call to GetNames (or whatever the method is) I want to grab the data from the database. I want to save the results in cache and on the second call to use the cached version if it exists.  Can anyone show an example of how this would work, where this should be implemented (model?) and if it would work.  I have seen this done in traditional ASP.NET apps , typically for very static data. How to get a DOM Element from a jQuery selector? PyQGIS toggle group visibility (and recursively subsub...group visibility) I would like to set visibility of a layer group and all of its children (and grand-children and so on...) using PyQGIS (QGIS 2.14.1).  Assume the groups name is g0 with subgroups g0[1...n] and subsub...groups g0[1...n][1...n][...].  QgsProject.instance().layerTreeRoot().findGroup('g0').setVisible(False)   sets the group and ALL what comes beneath invisible, so far so good:    But vice versa  QgsProject.instance().layerTreeRoot().findGroup('g0').setVisible(True)   sets the group visible and leaves all its children untouched, wich results in nothing visible at all:    QgsProject.instance().layerTreeRoot().findGroup('g0').updateChildVisibility()   only touches the direct children and not recursively all the descendants:    I wonder why manually setting the root groups (g0) visibility does result in recursively setting the visibility of all beneath it at all.  Question: Do I have to implement some recursive function to set the visibility of a group and its whole big family, or is there a more convenient way to accomplish this? Or is here something buggy? The temperature and pressure everywhere inside the Sun reach the critical point to start nuclear reactions - there is no reason for it to take such a long time to complete the reaction process.  Just like a nuclear bomb will complete all the reaction within $10^{-6}$seconds.  Why does most of the hydrogen of the Sun still not react even though it reaches the critical point, and why take stars billions of years to run out of fuel? Down vote changed to up vote caused reputation meter to pass daily maximum