I have always been taught that I should use the base form of a verb after the word 'to'. But I sometimes see sentences such as 'I am looking forward to meeting you' &amp; 'She has devoted her life to doing charitable works'. So how to know when to use base form or verb+ing after the word 'to'? Thank you.
I want to see you.   I look forward to seeing you.      How can one say "to" in the first sentence is an infinitive marker and in the second sentence a preposition when we are given just the following two sentences and are asked to fill in the blanks?        I want to ____(see/seeing) you.   I look forward to __(see/seeing) you.
Where can I find the location of folders for installed programs? 14.04 --> 16.04 failed; apt (>= 1.0.1ubuntu2.13)' is not installed (This question was not resolved. Due to time constraints Computer was restored to factory settings.)  I was attempting to upgrade from 14.04 to 16.04, but apt threw this error:  The required dependency 'apt (&gt;= 1.0.1ubuntu2.13)' is not installed.   What does this mean, and how can I fix it?  When I type in the command apt-cache policy apt  Shageenth@shageenth-Inspiron-3451:~$ apt-cache policy apt apt: Installed: 1.0.1ubuntu2.11 Candidate: 1.0.1ubuntu2.11 Version table: *** 1.0.1ubuntu2.11 0 100 /var/lib/dpkg/status 1.0.1ubuntu2 0 500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64  Packages   The error happens when I run the command:   sudo do-release-upgrade -d   and it produces the following:  Checking for a new Ubuntu release Get:1 Upgrade tool signature [198 B] Get:2 Upgrade tool [1,265 kB] Fetched 1,265 kB in 0s (0 B/s) authenticate 'xenial.tar.gz' against 'xenial.tar.gz.gpg' extracting 'xenial.tar.gz'  Reading cache  Checking package manager Reading package lists... Done Building dependency tree Reading state information... Done Building data structures... Done  Required depends is not installed  The required dependency 'apt (&gt;= 1.0.1ubuntu2.13)' is not installed. What would be your preferred way to concatenate strings from a sequence such that between every two consecutive pairs a comma is added. That is, how do you map, for instance, ['a', 'b', 'c'] to 'a,b,c'? (The cases ['s'] and [] should be mapped to 's' and '', respectively.)  I usually end up using something like ''.join(map(lambda x: x+',',l))[:-1], but also feeling somewhat unsatisfied. Proofs of AM-GM inequality The arithmetic - geometric mean inequality states that $$\frac{x_1+ \ldots + x_n}{n} \geq \sqrt[n]{x_1 \cdots x_n}$$ I'm looking for some original proofs of this inequality. I can find the usual proofs on the internet but I was wondering if someone knew a proof that is unexpected in some way. e.g. can you link the theorem to some famous theorem, can you find a non-trivial geometric proof (I can find some of those), proofs that use theory that doesn't link to this inequality at first sight (e.g. differential equations …)?  Induction, backward induction, use of Jensen inequality, swapping terms, use of Lagrange multiplier, proof using thermodynamics (yeah, I know, it's rather some physical argument that this theorem might be true, not really a proof), convexity, … are some of the proofs I know. Is this true?  If $A$ and $B$ are sets, then $A=\emptyset $ if and only if $B = A \bigtriangleup B$.  If $A=\emptyset$ then $B=\emptyset$ too?  Could someone help me please? Pointing the camera in a particular direction programmatically I'm trying to use Python to place a camera. I know the camera's location, and the forward and up vectors for the camera (i.e. the direction it's pointing and its orientation). How do I do this?  I know that it's possible to calculate a raw world matrix from the above information, which I can then apply to the camera, but I was rather hoping not to have to. Is there an easier way? Editing a starred post in chat breaks display for user who starred it Steps to reproduce:   User A posts a message User B stars it, the star next to the post appears yellow User A edits the post The display of the star in User B's view becomes black, as if they haven't starred it   This is the worst bug ever in the history of StackExchange and makes the entire network completely unusable for me. I'm going to Yahoo! Answers until this is fixed. How to get child process from parent process Recursively delete empty directories in Windows Suppose there is a message that is encrypted with AES-128-CBC.  The message is as follows, new lines are used to delimit the 16 byte boundary for each block:  Wire funds from: Alice to Bob in   the amount of $ 1   Because this message is encrypted using CBC mode,  any modification of the first block of cipher text would propagate throughout the message.   However, the amount of the fund transfer falls in the last block.  I am under the assumption that an attacker can use the property of  to alter the last block and produce a valid amount that is greater than \$1 in far fewer than $2^{128}$ operations.   Is this a correct assumption?  Is there a name for this attack or do you know of a real world example?    My instinct is that if you just need one byte of the 16 byte block to be of a specific value then it would only require $2^8$ operations because the other 120 bits of the plain text could be any value. For example lets say we wanted the last block of cipher text to decrypt to 9\0 (where \0 denotes a single null byte, and the message would be interpreted as \$9), then it would take only $2^{16}$ operations to find this cipher text block.  Is there something I am missing? Which rational numbers can be written as the sum of two rational squares?  That is, for which rational numbers $a$, are there rational numbers $x$ and $y$ such that $a = x^2 + y^2$.  It is a famous theorem that if an integer can be written as the sum of two rational squares then it can be written as the sum of two integral squares, and then the solution is the famous one by Fermat, but I didn't find anything about the general case. I have 238gb of timelapse photos which was taken over a period of twenty days and all the photos are split up into 20 folders. I would like to put this together into a timelapse, I tried using Premiere Pro but that is taking very very long, any tips on putting it together fast btw Im on a Mac, thanks. Truly destroying a PHP Session? In chapter 2 section 7 (pg 151) of Hartshorne's algebraic geometry there is an example given that talks about automorphisms of $\mathbb{P}_k^n$. In that example Hartshorne states that $\mathcal{O}(-1)$ has no global sections. However, we know that $\mathcal{O}(1)$ is generated by global sections. This is stated at the first of the section that if $\mathbb{P}_k^n = Proj k[x_0,...,x_n]$ then the $x_0,...,x_n$ give rise to global sections $x_0,...,x_n\in\Gamma(\mathbb{P}_k^n,\mathcal{O}(1))$.  I guess I don't understand this twisted structure sheaf very well, or to be honest I don't think I understand structure sheaves in general as well as I would like. The twisting part seems simple at first- you shift the grading of Proj over and then take the structure sheaf.  Admittedly I don't feel comfortable using the structure sheaf other than using the basic facts about it that Hartshorne gives when it is introduced. If anyone could give some insight as to what's going on here or how I might be able to understand this better it would be much appreciated. Thanks. I see that the code in many packages and examples contains percent signs % at the end of (many) lines. What are they used for? Do they affect the parsing of those lines? I want to validate a set of credentials against the domain controller. e.g.:  Username: STACKOVERFLOW\joel Password: splotchy   Method 1. Query Active Directory with Impersonation  A lot of people suggest querying the Active Directory for something. If an exception is thrown, then you know the credentials are not valid - as is suggested in .  There are some serious  however:   You are not only authenticating a domain account, but you are also doing an implicit authorization check. That is, you are reading properties from the AD using an impersonation token. What if the otherwise valid account has no rights to read from the AD? By default all users have read access, but domain policies can be set to disable access permissions for restricted accounts (and or groups). Binding against the AD has a serious overhead, the AD schema cache has to be loaded at the client (ADSI cache in the ADSI provider used by DirectoryServices). This is both network, and AD server, resource consuming - and is too expensive for a simple operation like authenticating a user account. You're relying on an exception failure for a non-exceptional case, and assuming that means invalid username and password. Other problems (e.g. network failure, AD connectivity failure, memory allocation error, etc) are then mis-intrepreted as authentication failure.   Method 2. LogonUser Win32 API   have suggested using the  API function. This sounds nice, but unfortunately the calling user sometimes needs a permission usually only given to the operating system itself:     The process calling LogonUser requires   the SE_TCB_NAME privilege. If the   calling process does not have this   privilege, LogonUser fails and   GetLastError returns   ERROR_PRIVILEGE_NOT_HELD.       In some   cases, the process that calls   LogonUser must also have the   SE_CHANGE_NOTIFY_NAME privilege   enabled; otherwise, LogonUser fails   and GetLastError returns   ERROR_ACCESS_DENIED. This privilege is   not required for the local system   account or accounts that are members   of the administrators group. By   default, SE_CHANGE_NOTIFY_NAME is   enabled for all users, but some   administrators may disable it for   everyone.   Handing out the "Act as a part of the operating system" privilege is not something you want to do willy-nilly - as Microsoft points out in a :     ...the process that is calling   LogonUser must have the SE_TCB_NAME   privilege (in User Manager, this is   the "Act as part of the Operating   System" right). The SE_TCB_NAME   privilege is very powerful and   should not be granted to any arbitrary user just so that they can   run an application that needs to   validate credentials.   Additionally, a call to LogonUser() will fail if a blank password is specified.    What is the proper way to authenticate a set of domain credentials?    I happen to be calling from managed code, but this is a a general Windows question. It can be assumed that the customers have the .NET Framework 2.0 installed. Can Tamron 16-300mm Macro Lens fit to Canon EOS 600D? I use Canon EOS 600D and I want a lens with a larger range. I found out Tamron 16-300 f/3.5-6.3 Di II VC PZD Macro Lens, I added it into my wishlist. I did some research on it and I'm scared that it couldn't fit to my Canon EOS 600D.  I'm still a beginner... I'm confused with EF, EF-S and APS-C/DX. Can someone please explain it to me? Can 'AMD-only' RAM really be restricted to AMD chipsets, and if so, why? I was browsing for a RAM upgrade earlier for my system, and came across 'AMD-only' RAM (aka, RAM that only works on AMD chipsets).  This RAM can , and seems to be slightly cheaper than 'normal' RAM.  The RAM prompts a question: is this RAM really restricted to AMD chipsets?  When considering RAM for a system, there are certain considerations to make such as:   Speed (1066MHz, 1600MHz, etc); CAS (latency, lower is better); Generation (DDR2, DDR3, DDR4, etc)   However there is usually no such consideration as chipset compatibility. Sure, it's possible to guarantee that a given stick of memory will work if it's within the bounds of the chipsets listed in the information given by the seller/manufacturer.  For instance if a series of chipsets supported RAM between 1600MHz and 2400MHz, with 9-12 CAS, and on DDR3, it would be possible to list a product as being fully compatible with that series of chipsets if the said RAM was 2000MHz, 10 CAS, and DDR3.  I suspect that's partially the story here. However, is it possible at all for a given stick of memory to be 'AMD-only' or 'Intel-only', and if so, how? Why are my villagers attempting to breed (they have the red hearts) but then stop breeding suddenly and gray "angry" particles pop up? I set up a villager breeder and set down 4 beds with 2 villagers in the middle and a carrot farmer supplying them with carrots. The first time both of those villagers bred the breeder worked perfectly fine. After that, however, the gray angry particles popped up every time they would try to breed (they would engage in breeding at a normal pace, just could not actually produce a baby). I even killed the one villager they produced in case it took a bed and even then, the two villagers would not breed anymore. Is there something I have done wrong? This seems odd considering they were only able to breed once and even by eliminating their offspring the villagers could not breed again. Edit: version is 1.16.4 Asking on Multiple Sites: "Soft-Migration" See also:   Many of the newer sites have a certain degree of overlap. With the creation of Chem.SE, I noticed quite a few questions on Physics.SE which could have benefited from the chem community and vice versa. There also are a few that could benefit from bio.SE.. Now these questions don't warrant a migration. They can be double-posted, but this doesn't lead to a smooth experience. Even when cross-linked, changes to either post (new answers,new comments,etc) aren't effectively relayed to the other site, and the two questions are just that-- two, separate questions. One solution that came to my mind was a &quot;soft migration&quot; option for mods. By this, a question on site A stays on site A. But, it appears in the site B question list as well. Edits/answers should bump it. Basically, there will be a placeholder item in the questions list of site B. It shows the votes/views/answers of the post on site A, along with the tags (maybe stylized differently). These should be an unobtrusive way to quickly identify what the site is. The post should also be bumped whenever the post is bumped on Site A, and it should display the rep/time/etc of the bumping user as usual. Here's a quick mockup of what happens on the site B question list:  Without being obtrusive or in-your-face (stuff like [migrated] is sort of in-your-face), the post is elegantly shown to be on Physics.SE (well, if you know the icon, anyway). The tags are italicized to show that they link to a different site tags, and the &quot;bumping user&quot; (me) has his/her rep on that site shown. We can also add an indicator on the question on site A () that shows that it was soft-migrated. We can use tooltips as well on the icons to tell us why they're here. After all, half of SE documentation is in tooltips.  Now I know that these issues will probably be raised:  Rep: An avid user on Site B gets no Site B rep for giving a good answer on Site A. Frankly, I don't care about this to much, but others may.  Implementation: It may get complicated. Internally, I'd propose that none of the question data is copied, rather Site A pushes the vote/bump data whenever a vote/bump happens. The easiest way to then implement the soft merge would be to have a table of questions soft-merged &quot;to&quot; site B on site B itself, with columns for all the vote/etc data. The questions table should have an extra column for &quot;soft-migrated to&quot;--that way Site A can determine where to push new data to on every vote/bump. Now, all Site B has to do is take the JOIN of the questions table and the soft-merge table and display them in the new questions list (or any list, for that matter). With some extra formatting, maybe. Of course, I may be oversimplifying this and I don't really know what I'm talking about ;-)  Is there a need? : Yes, I would say so. Such questions can get awesome answers is both the communities participate, but our don't-cross-post-much policy deters this. In the end, this will result in better post quality, making the Internet better. Also, as area51 grows, we will see this problem more and more, and this will become more and more necessary.   Thoughts? Any better ideas? Waffles?  Update: Another use case for this would be to soft migrate all MSO  questions over to child metas, effectively solving