Java is pass by value or pass by reference when collections or array is passed as parameter?
Is Java "pass-by-reference" or "pass-by-value"?
Meta Theory when studying Set Theory What exactly serves as the meta theory in the study of set theory (for example in Kunen's text). It seems to involve a certain amount of number theory and a certain concept of what it means to be finite.   Also: We usually use $\bigcup_{\alpha\in{ON}}R_{\alpha}$ as our set theortic universe $V$ (in the sense we believe that all sets we are interested in live there) where $R_{0}=\emptyset$, $R_{\alpha+1}= \mathcal{P}(R_{\alpha})$ and $R_{\alpha}=\bigcup_{\beta&lt;\alpha}R_{\beta}$ when $\alpha$ is a limit ordinal. The study of independence results then seem to be based on relatavizing notions with this $V$ as our set theoretic universe. It seems that it is implicitly assumed that the $\omega$ in $V$ has no non-standard elemements (in the sense that there is no $n&gt;a$ in $\omega$ where $a$ is obtained be repeatedly applying the successor operation to $0$.) Is this true and can it be formalized or is it something that is taken for granted?   e.g. If the above were true then $ZFC\vdash{\neg{Con(\ulcorner{ZFC}\urcorner)}}$ would imply that $ZFC$ is inconsistent since we may look at the $ZFC$ axioms $\phi_{1},...,\phi_{n}\vdash\neg{Con\ulcorner{ZFC}\urcorner}$, then look at a ctm these axioms (which exists by reflection and downward Lowenheim Skolem) and recover the proof of the contradiction. QGIS color polygon according to points I have two layers. Layer 1 contains points (x,y) and layer 2 contains one polygon. All points in layer 1 are positioned within the polygon of layer 2. The points in layer 1 contain an attribute with information on the topography/elevation at the specific point. Can I color the polygon in layer 2 based on attributes from the points in layer 1 in order to create an elevation map? Where do I get the key for the first house? I've 'completed' the game, but didn't find the key for the first house. (I got the one for the arcade machine house). Where can I find it? If integral is zero and function is continuous and non negative, then what about the function? Why is "Nature" usually spelt with an initial capital letter in scientific journals? I am mainly referring to life science here, in case this matters.  I am not talking about the obvious cases, like capitalisation in titles, at the beginning of a sentence, etc., but when it appears mid-sentence, where one would normally expect it to be lowercase.  I've heard some explanation that it gives the impression of Nature as a goddess (see comments on this post ) - but this is probably the last thing I would have expected in a scientific article... Output of which command used for input to cd I would like to take the output of a which command, and cd to the parent directory. For example, say I have the following:  which someprogram   With output:  /home/me/somedirectory/someprogram   And I would like to cd to the directory that someprogram lives in:  cd /home/me/somedirectory   I'd like to accomplish this in one line. What is the most elegant, tricky, short way to do this? I am having difficulty with this proof. I have previously proved that for an automorphism on the extension field $K$ of $F$ that when restricted to $F$ is the identity automorphism must take roots of $f(x)\in F[x]$ in $E$ to roots of $f(x)$ in $E$. I was thinking of using the minimal polynomial $x^{3}-2\in\mathbb{Q}[x]$ and the result of previous problem I solved, but I suspect there are automorphisms that don't fix the subfield, so the result can't be used or I need to prove that any automorphism of an extension field must fix the subfield that is being extended or always sends roots in $E$ to roots in $E$.  I am not asking for a solution to this, but maybe a hint or pointer in the right direction. This problem is introduced in the text prior to Galois theory, so please keep that in consideration. Seeking neighborhood boundaries globally? Besides Zillow's creative-commons licensed  shapefiles, what sources of neighborhood boundaries are there? Not just in the US, but all over the world.  Free/open source is ideal, but paid sources could be interesting too. What happens if I combine Ur-priest and prestige class to exceed 10 effective spellcasting levels? Suppose I have a human character who invested 5 levels on Wizard, 2 on Ur-priest(by appropriate feat chain), and 8 levels of Mystic Theurge, net level of 15. This allows you to cast spells as stated in 10th level Ur-priest Spells per day table. Now, assume that I leveled up, and I choose Mystic Theurge as the next level class. This makes me to look up Ur-priest table for Level 11, which does not exist. In this case, what happens to my divine spells per day? Does it continue to progress "in the same pattern", as Hellfire Blast progresses with Hellfire Warlock-Legacy Champion build? Does it stop and I only get Wizard spells per day? Or, isn't it allowed to do so?  I am totally aware that although the answer is "yes", it does not mean it means spells over 9th level will be granted to my character unless I take Improved Spell Capacity, which requires me to be epic. What I am curious is the progression of spells per day of existing spells.  P. S. Don't ask me how to satisfy the requirements. This is possible by combining Apprentice (Criminal), Iron Will and Great Fortitude as level-up feat, and Spell Focus (evil) as a Wizard bonus feat (RAW, it is a "Spell Focus" feat, anyway.) I'm talking about the movie  Spoilers ahead.  Walter (Daniel Radcliffe) gave the task or blackmailed the Four Horsemen to steal a chip from a lab which can access any digital device. So they did steal the chip. And when they rescue Dylan Rhodes (Mark Ruffalo) from drowning in the water, Jack Wilder said that the chip is fake.     Jack: Wait something is not right.      Atlas: What's wrong?      Jack: It's fake.   Then they assumed that Walter did not know that the chip is fake. So they came with a plan to bluff. They pretended that they had the real chip. After they got caught by Walter, they gave the fake chip to Walter. Walter checked the chip and declared it as real. The Four Horsemen were surprised.     Walter: I'm sorry to interrupt. But I have to say congratulations and   thank you. It's real.      Lula: What? It's real!!!!!      Atlas: What? Is it real?      Jake: What is he talking about?   What happened? I didn't get it. What did I miss? Was the chip real? Was Walter pretending it to be real? If so, then why? If not, who switched the real chip with the fake one? Who had the real chip before? Showing the sequence converges to the square root For any $a &gt; 0$, I have to show the sequence $x_{n+1}$ $=$  $ \frac 12$($x_n+ $ $ \frac {a} {x_n}$)  converges to the square root of $a$ for any $x_1&gt;0$.  If I assume the limit exists ( denoted by $x$) then,  $x$ $=$  $ \frac 12$($x+ $ $ \frac {a} {x}$) can be solved to $x^2 = a$  How could I show that it does exist? What is the origin of "man on the spot"? What is the origin of "man on the spot" ?   defines on the spot and uses as an example man on the spot.     on the spot -  at the place in question; there; "they were on the spot when it happened"; "it had to be decided by the man on the   spot" (Emphasis added)   Some evidence suggests that the origin of the phrase refers to decisions made by officials of the past British empire and actions taken by them. Why are Only Real Things Measurable? Why can't we measure imaginary numbers? I mean, we can take the projection of a complex wave to be the "viewable" part, so why are imaginary numbers given this immeasurable descriptor? Namely with operators in quantum mechanics, why must measurable quantities be Hermitian, and consequently real? How to divide two 64-bit numbers in Linux Kernel? Some code that rounds up the division to demonstrate (C-syntax):  #define SINT64 long long int #define SINT32 long int  SINT64 divRound(SINT64 dividend, SINT64 divisor) {   SINT32 quotient1 = dividend / divisor;    SINT32 modResult = dividend % divisor;   SINT32 multResult = modResult * 2;   SINT32 quotient2 = multResult / divisor;    SINT64 result = quotient1 + quotient2;    return ( result ); }   Now, if this were User-space we probably wouldn't even notice that our compiler is generating code for those operators (e.g. divdi3() for division). Chances are we link with libgcc without even knowing it. The problem is that Kernel-space is different (e.g. no libgcc). What to do?  Crawl Google for a while, notice that pretty much everyone addresses the unsigned variant:  #define UINT64 long long int #define UINT32 long int  UINT64 divRound(UINT64 dividend, UINT64 divisor) {   UINT32 quotient1 = dividend / divisor;    UINT32 modResult = dividend % divisor;   UINT32 multResult = modResult * 2;   UINT32 quotient2 = multResult / divisor;    UINT64 result = quotient1 + quotient2;    return ( result ); }   I know how to fix this one: Override udivdi3() and umoddi3() with do_div() from asm/div64.h. Done right? Wrong. Signed is not the same as unsigned, sdivdi3() does not simply call udivdi3(), they are separate functions for a reason.  Have you solved this problem? Do you know of a library that will help me do this? I'm really stuck so whatever you might see here that I just don't right now would be really helpful.  Thanks, Chad How can I know which radio button is selected via jQuery? Use physical harddisk in Virtual Box Using Virtual Box, how can I install an OS to a secondary, physical disk, and boot it in both (at separate times) Virtual Box, and as a typical secondary OS install? homemade chilli oil I am making chilli oil using light olive oil, crushed chilli, dried garlic, dried fennel seeds and parsley.  I have been making this for years. I am concerned about this Botulinum business. Should I be concerned? And what can i do to avoid this?  Currently, I heat the olive oil before putting it into the mixture, jar it, and normally keep it in the cupboard for months, with no problems with taste.  Another thing I am wondering is, how does one measure the expiry date on homemade chilli oil? Can someone help? Number of homomorphisms from $(\mathbb Q^+ , \,\cdot\,)$ to $(\mathbb Z_n , +)$ How many homomorphism are there from $(\mathbb Q^+ , \,\cdot\,)$ to $(\mathbb Z_n , +)$?   Could anyone give a hint how to proceed? I couldn't even start Error propagation with asymmetric uncertainties I red the Wikipedia  on error propagation. I get into some trouble when I want to calculate the error propagation in a specific case. I have real numbers $A$ and $B$ with related upper ($\Delta A_u$, $\Delta B_u$) and lower ($\Delta A_l$, $\Delta B_l$) uncertainties. I have two functions calculated as follows: $$F = \sqrt{A^2+B^2}$$ and  $$G = \tan^{-1}\frac{B}{A}$$ What are the related upper and lower errors of $F$ and $G$?  I found general formulae for Gaussian error distributions ($\Delta A_u = \Delta A_l$ and $\Delta B_u = \Delta B_l$), for instance the first formula of the first answer on . Is there a way to generalize that formula for arbitrary distributions with asymmetric errors as in my example? If $A$ and $B$ are positive definite, then is $B^{-1} - A^{-1}$ positive semidefinite?