love between husband and wife   What is the reason that there is no article (e.g. "love between a husband and a wife") in the above? Has some kind of a rule been identified grammatically when it comes to such a case? If I were to guess I think it's because the indefinite article 'a', the purpose of that, is taking a generic sample (or 'instance') from a 'class' (the class of husbands), but in the above sentence you want to refer to the class itself... the husband class and the wife class... and not an 'instance' of them, because it just is more to the point. Do you think this is a fair reasoning? Also, a thought came to me that with the use of the indefinite article, you get a generic husband and a generic wife, which, may not necessarily love each other (for they are not a specific pair of a specific husband and a specific wife who in fact love each other).
Here's a fragment from Jack London's Star Rover:     Wordsworth knew. He was neither seer nor prophet, but just ordinary man like you or any man. What he knew you know, any man knows. But he most aptly stated it in his passage that begins "Not in utter nakedness, not in entire forgetfulness.   To the best of my — admittedly sketchy — knowledge of grammar, the second sentence should read neither a seer nor (a) prophet, but just an ordinary man. Even if we accept the seer and the prophet as "poetic entities" ("father and son," "robber and robbed," "man to man," or whatever), logic would still dictate that ordinary man should be preceded by an an.  It is a well-known fact that Jack London's usage wasn't always up to par; his grammar, on the other hand, was always top-notch.  Logically, the sentence is grammatically incorrect (correct me if I'm wrong: no pun intended).  Illogically, it reads smoothly: intuitively, a native speaker understands that there's nothing wrong here.  However, those to whom English is not the first language cannot be expected to be intuitive in this case and would want an explanation. Any suggestions?
How do I summon the Golem? In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself).  When I export from QGIS to PDF, I don't appear to have the option for this.  Does QGIS support preserving layers when exporting to PDF?  Is there a special setting needed to enable this capability?  Or has anyone wrote a plugin for this feature? Why do the $n \times n$ non-singular matrices form an "open" set? Why is the set of $n\times n$ real, non-singular matrices an  open subset of the set of all $n\times n$ real matrices? I don't quite understand what "open" means in this context.  Thank you. What is the definition of $2.5!$? (2.5 factorial) I was messing around with my TI-84 Plus Silver Edition calculator and discovered that it will actually give me values when taking the factorial of any number $n/2$ where $n$ is any integer greater than $-2$. Why does this happen? I thought factorials were only defined for positive integers and $0$, so what is my calculator doing to get the answer $3.32335097$ when I enter $2.5!$? Is there actually a definition of $2.5!$ or is my calculator just being weird? How is the factorial function implemented?  I understand the binary implications of $2.5$, so that could possibly have something to do with it. I get a domain error when trying to take the factorial of $-1, 2.3, e$, and any number that is not of the form $n/2$ where $n$ is any integer greater than $-2$. How to simulate from a Gaussian copula? Suppose that I have two univariate marginal distributions, say $F$ and $G$, which I can simulate from. Now, construct their joint distribution using a , denoted $C(F,G;\Sigma)$. All the parameters are known.  Is there a non-MCMC method for simulating from this copula? Find the number of solutions of $a_0+a_1+a_2=17$ if $2\le a_0\le 5$,   $3\le a_1\le 6$, $4\le a_2\le 7$.   This is an exmaple given by my professor, and his solution is:       The number of solutions to this equation satisfying the given   constraints is equal to the coefficient of $x^{21}$ in the expression   $$\left(\sum_{n=2}^5x^n\right)\left(\sum_{n=3}^6x^n\right)\left(\sum_{n=4}^7x^n\right)=x^9\left(\sum_{n=0}^3x^n\right)\left(\sum_{n=0}^3x^n\right)\left(\sum_{n=0}^3x^n\right).$$   This must be 3, since the coefficient of $x^8$ in $(1+x+x^2+x^3)^3$ is   3.   I understand actually nothing here. The expression of summation just pops up, and then comes the answer. What I only know that the idea of generating function is used here. Can someone help explain how the steps in the solution come? Is there any option with 'ls' command that I see only the directories? Sometimes, I need to check only the directories not files. Is there any option with the command ls? Or is there any utility for doing that?  EDIT: I'm using Mac OS X, and ls -d gives me . even though I have directories. What exactly determines depth of field? There are several questions here about , about , and about . And of course there's the basic . And plenty of  questions. There's related questions like . But there's no be-all-end-all question asking:  What exactly determines depth of field in a photograph?   Is it just a property of the lens? Can lenses be designed to give more depth of field for the same aperture and focal length? Does it change with camera sensor size? Does it change with print size? How do those last two relate? Remap Caps Lock to Ctrl-b Using jQuery, how do I change the elements html value? (div) Using a ajax request I want to change content of my div.  &lt;div id="d1"&gt;202&lt;/div&gt;   So I want to change the content to a different number.  $('d1').InnerText???   Also, say I wanted to increment the number, how could I do that? Do I have to convert to int? Graph for relationship between two ordinal variables What is an appropriate graph to illustrate the relationship between two ordinal variables?  A few options I can think of:   Scatter plot with added random jitter to stop points hiding each other. Apparently a standard graphic - Minitab calls this an "individual values plot". In my opinion it may be misleading as it visually encourages a kind of linear interpolation between ordinal levels, as if the data were from an interval scale. Scatter plot adapted so that size (area) of point represents frequency of that combination of levels, rather than drawing one point for each sampling unit. I have occasionally seen such plots in practice. They can be hard to read, but the points lie on a regularly-spaced lattice which somewhat overcomes the criticism of the jittered scatter plot that it visually "intervalises" the data. Particularly if one of the variables is treated as dependent, a box plot grouped by the levels of the independent variable. Likely to look terrible if the number of levels of the dependent variable is not sufficiently high (very "flat" with missing whiskers or even worse collapsed quartiles which makes visual identification of median impossible), but at least draws attention to median and quartiles which are relevant descriptive statistics for an ordinal variable. Table of values or blank grid of cells with heat map to indicate frequency. Visually different but conceptually similar to the scatter plot with point area showing frequency.   Are there other ideas, or thoughts on which plots are preferable? Are there any fields of research in which certain ordinal-vs-ordinal plots are regarded as standard? (I seem to recall frequency heatmap being widespread in genomics but suspect that is more often for nominal-vs-nominal.) Suggestions for a good standard reference would also be very welcome, I am guessing something from Agresti.  If anyone wants to illustrate with a plot, R code for bogus sample data follows.  "How important is exercise to you?" 1 = not at all important, 2 = somewhat unimportant, 3 = neither important nor unimportant, 4 = somewhat important, 5 = very important.  "How regularly do you take a run of 10 minutes or longer?" 1 = never, 2 = less than once per fortnight, 3 = once every one or two weeks, 4 = two or three times per week, 5 = four or more times per week.  If it  would be natural to treat "often" as a dependent variable and "importance" as an independent variable, if a plot distinguishes between the two.  importance &lt;- rep(1:5, times = c(30, 42, 75, 93, 60)) often &lt;- c(rep(1:5, times = c(15, 07, 04, 03, 01)), #n=30, importance 1            rep(1:5, times = c(10, 14, 12, 03, 03)), #n=42, importance 2            rep(1:5, times = c(12, 23, 20, 13, 07)), #n=75, importance 3            rep(1:5, times = c(16, 14, 20, 30, 13)), #n=93, importance 4            rep(1:5, times = c(12, 06, 11, 17, 14))) #n=60, importance 5 running.df &lt;- data.frame(importance, often) cor.test(often, importance, method = "kendall") #positive concordance plot(running.df) #currently useless   A related question for continuous variables I found helpful, maybe a useful starting point: How to create symbols from strings and set values for them? Let $been(x,y)$ denote "person x has been to place y."   Express “Every person has been to 2 or more places” using quantifiers and $been(x, y)$.  This one is completely stumping me. I'm sure that I haven't come across this kind of concept before, and can't wrap my head around how I would approach it. I suspect the quantifiers should be $∀x$, $∀y$, and that it may involve negating the statement "every person has been to one or zero places," but that's as far as I can manage to go. Any help greatly appreciated. How to check if jQuery.ajax() request header Status is "304 Not Modified"? Constrain to any 2 axes during transform? I want to be able to lock my translation/scale operations to two axes at a time, say xy, xz or yz. It currently takes two operations (one for each axis).  Example, say for a cylinder, I would like to reduce the radius. I currently have to scale on the x axis first, then on the y axis, or I have to manually input the scale values in the object properties panel.  This option is easily accessible in 3dsmax via the axis constraints command bar. Or I can click the intersecting area between the 3d manipulator of the axes in question and move in that plane. Is there a way to disable a specific JS script from a specific website? I want to disable a specific JS script from a specific website without disabling the javascript completely. Is there a way to do that ? Show that $\tan{(\pi/7)} \tan{(2\pi/7)}\tan{(3\pi/7)}=\sqrt{7}$ a command to list all packagas installed on the system and their installed files, how? How to avoid interference in wireless communication? I am working on wireless communication system. We are using around 10 pairs of transmitter and receivers. We are using atmega16 microcontroller for encoding and decoding by USART ports.  Now we are able to transmit the data and receive the same in the receiver end, but there is a major problem, when we are finding the 2 transmitter data coming at the same time. The receiver is unable to get it due to interference.  Suppose one transmitter sends "SENDA" at the meanwhile another transmitter sends "GETTS", at that time the receiver can not receive proper data. As all the transmitters and receivers are working in same frequency, so this interference is occurring. How can I resolve this issue? How do I completely uninstall Google Chrome and Chromium? I'm having a problem with Chrome and one of its extensions, so I want to completely uninstall everything. I've uninstalled Chrome through the Software Center, but when I reinstall it, all of my extensions and preferences are still there.   If I want to start over from scratch, what do I need to do?