I have a problem - I bought a book "Introduction to Time Series and Forecasting" by Brockwell and Davis. The first chapter was ok, but now at chapter 2 I am totally lost - I cannot figure the main idea of the explanation, and I cannot figure the intermediate steps in the author results - so the maths becomes useless. I have no background in stochastic processes.  Can someone recommend a book similar to Brockwell &amp; Davis in contents, but where proofs are given without "It can be shown that..." (with intermediate steps), and which has a more coherent explanations since I do not understand anymore why the author is giving the details of all these propositions in Brockwell book. I need the book for self-study.
I started by Time Series Analysis by Hamilton, but I am lost hopelessly. This book is really too theoretical for me to learn by myself.   Does anybody have a recommendation for a textbook on time series analysis that's suitable for self-study?
How to make a bibliography (for total beginners)? Proving that a doubly-periodic entire function $f$ is constant. Let $f: \Bbb C \to \Bbb C$ be an entire (analytic on the whole plane) function such that exists $\omega_1,\omega_2 \in \mathbb{S}^1$, linearly independent over $\Bbb R$ such that: $$f(z+\omega_1)=f(z)=f(z+\omega_2), \quad \forall\,z\in \Bbb C.$$Prove that $f$ is constant.   The intuition seems clear to me, we have the three vertices of a triangle given by $0$, $\omega_1$ and $\omega_2$. All points in the plane are one of the vertices of that triangle under a suitable parallel translation. The constant value will be $f(0)$, fine. Throwing values for $z$ there, I have found that $$f(n\omega_1) = f(\omega_1) = f(0)=f(\omega_2) = f(n\omega_2), \quad \forall\, n \in \Bbb Z.$$  I don't know how to improve the above for, say, rationals (at least). Some another ideas would be:   Checking that $f' \equiv 0$. I don't have a clue of how to do that. Write $w = a\omega_1+b\omega_2$, with $a,b \in \Bbb R$, do stuff and conclude that $f(w) = f(0)$. This approach doesn't seem good, because I only have a weak result with integers above. Finding that $f$ coincides with $f(0)$ on a set with an accumulation point. This seems also bad: the set on with $f$ coincides with $f(0)$ by which I found above is discrete.    Nothing works and this is getting annoying... And I don't see how analyticity comes in there. I'll be very thankful if someone can give me an idea.  (On a side note.. I know that this title is not informative at all. Feel free to edit if you come up with something better.) Move all files of type to a new folder in windows 7 Will the Android app be receiving any future updates? Will there be a new version of the Android app? It's been without any update for a long time and it doesn't seem to be working really well. how to use dom php parser Where does the word "torsion" in algebra come from? Torsion is used to refer to elements of finite order under some binary operation. It doesn't seem to bear any relation to the ordinary everyday use of the word or with its use in differential geometry (which relates back to the ordinary use of the word). So how did it acquire this usage in algebra?  I'm interested to understand the intuition behind why the word "torsion" was chosen for this notion, as well as when it was first used. I am trying to put in a switch and a light it controls in a storage building and  is how I wired it.   Click for larger view  When I checked the wiring it registered 120V when the switch was on, and right around 50V when the switch was off.  Why would power still be getting to the light (I'm guessing there is a problem with the switch) and why would it only be 50V?  Oh, and where everything branches off at the beginning I have a junction box there where all of the wires are joined there. Why are floating point numbers inaccurate? Can I choose which records are copied in a Partial Copy sandbox? We have a partial copy sandbox that we're using for development and testing.  This is really helpful as some of our applications internally store Salesforce id's.  However, there is a limitation with the partial copy as it only brings in 10,000 records per object from the production environment.  Unfortunately some of the id's we internally store are not being brought down into our partial copy which causes errors.  The 10,000 records that it did copy over aren't needed; I realistically only need 1 or 2.  Is there any way I can achieve copying over a specific record from the production environment? Is there a way to use the covariance matrix to find coefficients for multiple regression? For simple linear regression, the regression coefficient is calculable directly from the variance-covariance matrix $C$, by  $$ C_{d, e}\over C_{e,e} $$ where $d$ is the dependent variable's index, and $e$ is the explanatory variable's index.  If one only has the covariance matrix, is it possible to calculate the coefficients for a model with multiple explanatory variables?   ETA: For two explanatory variables, it appears that $$\beta_1 = \frac{Cov(y,x_1)var(x_2) - Cov(y,x_2)Cov(x_1,x_2)}{var(x_1)var(x_2) - Cov(x_1,x_2)^2} $$ and analogously for $\beta_2$. I'm not immediately seeing how to extend this to three or more variables. How to escape quotes in shell? I'm having trouble with escaping characters in bash. I'd like to escape single and double quotes while running a command under a different user. For the purposes of this question let's say I want to echo the following on the screen:  'single quote phrase' "double quote phrase"   How can I escape all the special chars, if I also need to switch to a different user:  sudo su USER -c "echo \"'single quote phrase' \"double quote phrase\"\""   Of course, this doesn't produce the right result. broadcast receiver for missed call in android By definition $\aleph_1 = 2 ^{\aleph_0}$. And since $2 &lt; \aleph_0$, then $2^{\aleph_0} = {\aleph_1} \le \aleph_0 ^ {\aleph_0}$. However, I do not know what exactly $\aleph_0 ^ {\aleph_0}$ is or how I could compute it. Maybe I'm searching for the wrong thing, but I can't see how I can do this.  I have two servers:   Server A (has SQL Server 2012 installed) Server B (has SQL Server 2014 installed)   Server A provides an API via IIS. The code both inserts and gets data from the database depending on the API call.  Server B does exactly the same for its local database.  I would like to have it so that the two databases are consistent copies of each other. I do believe this is what HA accomplishes.   So a load balancer, for example, might direct API calls to A sometimes, and B sometimes, but the data needs to be consistent either way.  I found some documentation on HA for SQL Server 2012, but not on how to do this for a mixed environment of 2012 and 2014.  Any help or pointers to documentation would be great! Thanks. I'm getting pretty close to the reputation where I can start to edit others' posts, and I'm wondering what the etiquette for when (and when not) to do so. I figure that I should edit in the following circumstances:  Grammatical or spelling errors. Clarification where the meaning is not changed. For instance if the title does not describe the question very well. Where the user has made a very minor mistake that doesn't justify a full post to clarify. To add related resources or links that will help someone answer the post, or provide context  Before the commenting feature was added, I noticed that some moderators edit posts in order to insert a reply or extension to the post. I feel this isn't good etiquette (but I could be wrong) because I don't know what to do with their changes when I come to re-edit or respond. I also feel that I should be very careful not to change the meaning of any question or answer, even if that meaning is misguided. What other rules would be best practice?  Signatures and fluff are discouraged and are fair game to be removed.  See, for example, this post by  and this post by  and also see .  Also see Jeff Atwood's response in the comments to How do I remove a configuration object from the active configuration? I'm writing a custom module for Drupal 8. It defines a field storage configuration object, in a file called modules/mymod/config/install/field.storage.bloom_stem.bs_twitter_ac.yml.  The problem is that this is not removed when I uninstall the module; it is apparently left behind because, when I re-install the module, I get a crash.   drush -y pm-uninstall mymod drush cr drush -y en mymod      exception 'Drupal\Core\Config\PreExistingConfigException' with message 'Configuration objects (field.storage.bloom_stem.bs_twitter_ac) provided by mymod already exist in active configuration'   So it seems I need to some how manually remove this configuration object. Do I need to provide some more code that deletes it when the module is uninstalled? Any javascript event occurring when user clicks Stop load button? How is the skillset of an evolution being chosen? You may already know that if you catch two Pidgeys, they may have a different skillset.  I've also seen that evolving them from different skillsets will also create Pidgeottos with different skillsets.  Are those skills chosen randomly or do they follow a specific pattern? (Like Pidgey pattern 1 will always evolve into Pidgeotto pattern 1.)  If they are specific, is there a website to check for them? How caret calculates R Squared From the training output below, it looks like R squared is not calculated by the traditional formula 1 - SSE/SST, since lower error rate has lower R squared. So how is it calculated?    colsample_bytree  min_child_weight  RMSE      Rsquared    0.4               3                 16963.39  0.8799191   0.4               5                 16813.24  0.8788395 False proof that $ρe^{iθ} = ρ$ and so complex numbers do not exist? My professor showed the following false proof, which showed that complex numbers do not exist. We were told to find the point where an incorrect step was taken, but I could not find it. Here is the proof: (Complex numbers are of the form $\rho e^{i\theta}$, so the proof begins there) $$\large\rho e^{i\theta} = \rho e^{\frac{2 \pi i \theta}{2\pi}} = \rho (e^{2\pi i})^{\frac{\theta}{2\pi}} = \rho (1)^{\frac{\theta}{2\pi}} = \rho$$ $$Note: e^{i\pi} = -1, e^{2\pi i} = (-1)^2 = 1$$ Since we started with the general form of a complex number and simplified it to a real number (namely, $\rho$), the proof can claim that only real numbers exist and complex numbers do not. My suspicion is that the error occurs in step $4$ to $5$ , but I am not sure if that really is the case.