Why R is not significant (and very low), while all predictors are significant?
Significance contradiction in linear regression: significant t-test for a coefficient vs non-significant overall F-statistic
Why is it safe to use 15 A receptacles on a 20 A circuit? Is a contradiction enough to prove a set equality to $\varnothing$? I am relatively new to game development, and am working on a simple 2D platformer. I have created a tilemap and painted some tiles for the character to walk on.. but he is getting stuck. Yes, I know this is a common question and I did find some answers (including this one: ), but none seem relevant for me. The thing is my tiles are not flat.. they have pointy edges due to grass.. see the image below:  As you can see, the edge is not flat. I have overcome the problem of getting stuck by changing the &quot;Edge Radius&quot; to what you see in the above screenshot and that works, but the character now looks like he is floating slightly above the ground. Is there any way I can just tell Unity to ignore the jagged grass and make the collider flat and move the edge of it down a bit? That way it would fix the issue and also have the added bonus of looking like some of the grass is behind him and some in front.. Today, when you accept an answer you did not provide, you get a +2 reputation, however, if you accept your own answer, you get +0.  I expect the reason for this is to stop people gaming the system by asking and answering their own questions repeatedly.  However, this has the downside of providing a disincentive of accepting your own answer when it seems the best and instead accepting an inferior one in order to get the reputation bonus.  Therefore, I propose that the accept your own answer is only worth zero when there are no answers provided by anyone other than yourself.  I feel this keeps the intent of preventing gaming the system for reputation, while removing disincentive from picking the best answer, even if it is your own. I'm desperatly confused by notations and formulations so if someone could clarify the following things a little Í would be deeply grateful. The Lie algebra $\mathfrak{so}(1,3)_+^{\uparrow}$ of the proper orthochronous Lorentz group $SO(1,3)_+^{\uparrow}$ is given by \begin{equation} [J_i,J_j]=i \epsilon_{ijk} J_k \end{equation} \begin{equation} [J_i,K_j]=i \epsilon_{ijk} K_k \end{equation} \begin{equation} [K_i,K_j]=- i \epsilon_{ijk} J_k \end{equation} We can now define new generators with the old ones $N^{\pm}_i= \frac{1}{2}(J_i \pm i K_i)$ which satisfy \begin{equation} [N^{+}_i,N^{+}_j] = i \epsilon_{ijk} N^{+}_k ,\end{equation} \begin{equation} [N^{-}_i,N^{-}_j] = i \epsilon_{ijk} N^{-}_k ,\end{equation} \begin{equation} [N^{+}_i,N^{-}_j] = 0. \end{equation} where we can see that $N^{+}_i$ and $N^{-}_i$ make up a copy of the Lie algebra $\mathfrak{su}(2)$ each. My problem is to get what is going one here mathematically precise. Are the following statements correct and if not why:  When we build the new operators from the old generators we complexified $\mathfrak{so}(1,3)_+^{\uparrow}$ \begin{equation}(\mathfrak{so}(1,3)_+^{\uparrow})_\mathbb{C} = \mathfrak{so}(1,3)_+^{\uparrow}\otimes \mathbb{C} \end{equation} We saw that $\mathfrak{so}(1,3)_+^{\uparrow})_\mathbb{C}$ is isomorph to two copies of the complexified Lie algebra of $\mathfrak{su(2)}$: $(\mathfrak{so}(1,3)_+^{\uparrow})_\mathbb{C} \simeq \mathfrak{su(2)}_{\mathbb{C}} \oplus \mathfrak{su(2)}_{\mathbb{C}} $. Where exactly did we need that $\mathfrak{su(2)}$ is complexified here? The Lie algebras defined by $N^{\pm}_i$ are exactly those of $\mathfrak{su(2)}$ and we never use complex linear combination of $N^{\pm}_i$ or am I wrong here? $\mathfrak{su(2)}_{\mathbb{C}}$ is isomorph to $(\mathfrak{sl}(2,\mathbb{C}))_\mathbb{C}$: \begin{equation}\mathfrak{su(2)}_{\mathbb{C}} \simeq (\mathfrak{sl}(2,\mathbb{C}))_\mathbb{C} \end{equation} Here $(\mathfrak{sl}(2, \mathbb{C}))_\mathbb{C}$ denotes the complexified Lie algebra of $SL(2,\mathbb{C})$ Is $(\mathfrak{so}(1,3)_+^{\uparrow})_\mathbb{C} \simeq (\mathfrak{sl}(2, \mathbb{C}))_\mathbb{R}$ correct?  Here $(\mathfrak{sl}(2, \mathbb{C}))_\mathbb{R}$ denotes the real Lie algebra of $SL(2,\mathbb{C})$ Is $(\mathfrak{so}(1,3)_+^{\uparrow})_\mathbb{C} \simeq (\mathfrak{sl}(2, \mathbb{C}))_\mathbb{C} \oplus (\mathfrak{sl}(2, \mathbb{C}))_\mathbb{C}$ correct?  I looked this topic up in different books and each seemed to state something different. One book even used three differrent versions of $\mathfrak{sl}(2,\mathbb{C}) $ namely: $\mathfrak{sl}(2,\mathbb{C}) $, $(\mathfrak{sl}(2,\mathbb{C}))_\mathbb{C}$ and $(\mathfrak{sl}(2,\mathbb{C}))_\mathbb{R}$.  states simply that $\mathfrak{sl}(2,\mathbb{C}) $ is the complexification of $\mathfrak{su(2)}$ without making any reference to $SL(2,\mathbb{C})$ which does not help me either. Any help would be great. I'm using python\pyodbc and would like to access the second result set of a stored procedure. As near as I can tell, pyodbc does not support multiple result sets. Additionally, I can't modify the stored procedure. Are there any options to access the second result set using SQL or some other work-around? Perhaps create a second stored procedure that only returns the second result set of the first? Why does the symbol for the multiplication operation change shape? Why does the "$\times$" used in arithmetic change to a "$\cdot$" as we progress through education? The symbol seems to only be ambiguous because of the variable $x$; however, we wouldn't have chosen the variable $x$ unless we were already removing $\times$ as the symbol for multiplication. So why do we? I am very curious. It seems like $\times$ is already quite sufficient as a descriptive symbol. $X$,$Y$,$Z$ mutually independent implies $X+Y$ independent of $Z$ Positivity of a determinant My tweets are not showing up in other people's mentions My replies are not showing up in other people's mentions. I tried tweeting several friends, my other accounts but my tweets just won't appear in their mentions? They do appear on my own Twitter page. It's been almost 24 hours now and it's pretty frustrating. How do I fork a process that doesn't die when shell exits? List of freely available physics books I'm trying to amass a list of physics books with open-source licenses, like Creative Commons, GPL, etc. The books can be about a particular field in physics or about physics  in general.  What are some freely available great physics books on the Internet? edit: I'm aware that there are tons of freely available lecture notes online. Still, it'd be nice to be able to know the best available free resources around.  As a starter:         Table of contents sorted by field (in alphabetical order): why is the set of all binary sequences not countable? Relationship between $R^2$ and correlation coefficient Intuitive examples of importance sampling My background is computer science. I am fairly new to monte carlo sampling methods and, although I understand the math, I have hard time coming up with intuitive examples for importance sampling. More precisely, could someone provide examples of:    an original distribution one cannot sample from but one can estimate an importance distribution which can be sampled from and adequate for this original distribution. Does OpenSSH support multihop login? Ansible uses OpenSSH as the bottomed network communicative implementation, but does it support multi-hop login?   I mean, if Ansible can login a server directly, but can it log in server_a then from server_a login server_b for config the server_b? Is an Otyugh's grapple different from a standard grapple? In 5e to escape a Grapple check, I know you roll athletics (str) or acrobatics (dex) opposed by an athletics (str) check.  In the Otyugh entry in the Monster Manual it doesn't say there's any check, instead it assigns a set DC for an "escape" (DC 13... which is a str check with a 10 assigned as the "roll").    So the question is:    Does the Otyugh actually make a roll in this instance (like the general rule) or does it have a set DC (for the specific case) OR is it just a poorly communicated version of the GENERAL rule being played out?   A little clarification on this would be AWESOME. In the event of a "specific vs general" scenario, what actually is the "escape" roll?  What modifier is applied? None? How do I find out what fonts are used in a document/picture? Is it possible to identify the font used in a specific document/picture?  Answers to this question should identify:   Possible methods to do this (perhaps one answer per method) and adequately describe how to use it (as opposed to merely stating it); Ways of finding the identified fonts, if possible (free or not); and Any prerequisites associated with the method used, if required (for example, "In order to use method X, your document has to be in format Y").   This question is meant as an FAQ, based on an . Its aim is to facilitate the community with the general procedures involved in font identification. Similar cases are solved on a per-usage basis on 's  tag. How to convert numbers between hexadecimal and decimal Execute vs Read bit. How do directory permissions in Linux work?