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			<item>
		<title>Riemannian surfaces with an explicit distance function?</title>
		<link>http://mathoverflow.net/questions/37651/riemannian-surfaces-with-an-explicit-distance-function</link>
		<comments>http://mathoverflow.net/questions/37651/riemannian-surfaces-with-an-explicit-distance-function#comments</comments>
		<pubDate>Fri, 03 Sep 2010 19:06:37 +0000</pubDate>
		<dc:creator>Terry Tao</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://mathoverflow.net/questions/37651/riemannian-surfaces-with-an-explicit-distance-function</guid>
		<description><![CDATA[<p>I'm looking for explicit examples of Riemannian surfaces (two-dimensional Riemannian... <a href="http://mathoverflow.net/questions/37651/riemannian-surfaces-with-an-explicit-distance-function">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>I'm looking for explicit examples of Riemannian surfaces (two-dimensional Riemannian manifolds $(M,g)$) for which the distance function d(x,y) can be given explicitly in terms of local coordinates of x,y, assuming that x and y are sufficiently close.  By "explicit", I mean things like a description in terms of special functions, or by implicitly solving a functional equation or (at worst) an ODE, as opposed to having to solve a variational problem or a PDE such as the eikonal equation.</p>

<p>The only examples of this that I know of are the constant curvature surfaces, which can be locally modeled either by the Euclidean plane ${\bf R}^2$, the sphere ${\bf S}^2$, or the hyperbolic plane ${\bf H}^2$, for which we have classical formulae for the distance function.</p>

<p>But I don't know of any other examples.  For instance, the distance function on the surface of the solid ellipsoid or solid torus in ${\bf R}^3$ looks quite unpleasant already to write down explicitly.  Presumably Zoll surfaces would be the next thing to try, but I don't know of any tractable explicit examples of Zoll surfaces that are not already constant curvature.</p>

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		<item>
		<title>The Dold-Thom theorem for infinity categories?</title>
		<link>http://mathoverflow.net/questions/37647/the-dold-thom-theorem-for-infinity-categories</link>
		<comments>http://mathoverflow.net/questions/37647/the-dold-thom-theorem-for-infinity-categories#comments</comments>
		<pubDate>Fri, 03 Sep 2010 18:40:59 +0000</pubDate>
		<dc:creator>Eric Finster</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://mathoverflow.net/questions/37647/the-dold-thom-theorem-for-infinity-categories</guid>
		<description><![CDATA[<p>Let $\mathcal{M}$ denote the category of finite sets and monomorphisms, and let... <a href="http://mathoverflow.net/questions/37647/the-dold-thom-theorem-for-infinity-categories">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>Let $\mathcal{M}$ denote the category of finite sets and monomorphisms, and let $\mathcal T$ denote the category of based spaces.  For a based space $X \in \mathcal T$, one has a canonical funtor $S_X : \mathcal M \rightarrow \mathcal T$ defined by $\{n\} \mapsto X^n$.  The definition on morphisms is to insert basepoints on the factors which are not in the image of a given monomorphism.</p>

<p>As is well know, the homotopy groups of $\mathrm{colim} S_X = SP^\infty X$ give the homology of $X$ (this is the Dold-Thom theorem), and the homotopy groups of $\mathrm{hocolim} S_X = SP^\infty_h X$ given the stable homotopy of $X$.</p>

<p>Is there a model for $SP^\infty X$, the ordinary infinite symmetric product, as a homotopy colimit as opposed to a categorical colimit?</p>

<p>The motivation for this question comes from thinking about $\infty$-categories.  In an $\infty$-category, one does not really have a good notion (at least not one that I am aware of) of strict categorical colimits.  So I'm wondering if there is, nonetheless, some easily defined functor on the $\infty$-category of spaces which will let us calculate ordinary homology.  In short, is there any $\infty$-categorical analog of the Dold-Thom theorem?</p>

        ]]></content:encoded>
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		</item>
		<item>
		<title>Will my children owe taxes on my life insurance proceeds?</title>
		<link>http://money.stackexchange.com/questions/3395/will-my-children-owe-taxes-on-my-life-insurance-proceeds</link>
		<comments>http://money.stackexchange.com/questions/3395/will-my-children-owe-taxes-on-my-life-insurance-proceeds#comments</comments>
		<pubDate>Fri, 03 Sep 2010 17:49:03 +0000</pubDate>
		<dc:creator>Portman</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://money.stackexchange.com/questions/3395/will-my-children-owe-taxes-on-my-life-insurance-proceeds</guid>
		<description><![CDATA[<p>I had always thought that life insurance proceeds were not treated as taxable income.... <a href="http://money.stackexchange.com/questions/3395/will-my-children-owe-taxes-on-my-life-insurance-proceeds">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>I had always thought that life insurance proceeds were not treated as taxable income. From <a href="http://www.irs.gov/publications/p525/ar02.html#en_US_publink1000229373" rel="nofollow">IRS publication 525</a>:</p>

<blockquote>
  <p>Life insurance proceeds paid to you
  because of the death of the insured
  person are not taxable unless the
  policy was turned over to you for a
  price. This is true even if the
  proceeds were paid under an accident
  or health insurance policy or an
  endowment contract. However, interest
  income received as a result of life
  insurance proceeds may be taxable.</p>
</blockquote>

<p>However, when I <a href="http://www.google.com/search?q=life+insurance+proceeds+estate+tax" rel="nofollow">Google "life insurance proceeds estate tax"</a>, lots of scary-looking legal advice comes up, suggesting complex estate tax planning.  It's not clear to me whether this is a valid concern.</p>

<p>I'm not looking for a treatise on the estate tax; I just want to know: <strong>if my wife and I were to pass away, would our children have to pay taxes on our life insurance proceeds, or not?</strong></p>

        ]]></content:encoded>
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		<item>
		<title>Find a volume with a double integral</title>
		<link>http://mathoverflow.net/questions/37643/find-a-volume-with-a-double-integral</link>
		<comments>http://mathoverflow.net/questions/37643/find-a-volume-with-a-double-integral#comments</comments>
		<pubDate>Fri, 03 Sep 2010 17:40:46 +0000</pubDate>
		<dc:creator>TheMouse</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://mathoverflow.net/questions/37643/find-a-volume-with-a-double-integral</guid>
		<description><![CDATA[<p>I want to find the volume which is given with these inequalities: $(x^2 + y^2/9)^ 2... <a href="http://mathoverflow.net/questions/37643/find-a-volume-with-a-double-integral">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>I want to find the volume which is given with these inequalities:</p>

<p>$(x^2 + y^2/9)^ 2 ≤ z ≤ x^2y ,  $</p>

<p>$0 ≤ x $.</p>

<p>I know that I should use this formula,</p>

<p>$ \int\int ( z2(x,y) - z1(x,y) ) dx dy$  </p>

<p>(where $z2 = x^2y$ and $z1=(x^2 + y^2/9)^ 2 $
.</p>

<p>Is there any substitution which I could use? Or anything else...because when I try to do it..it seems an endless battle.</p>

<p>:)</p>

        ]]></content:encoded>
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		<title>4 week old nursing off and on constantly while awake</title>
		<link>http://moms4mom.com/questions/5739/4-week-old-nursing-off-and-on-constantly-while-awake</link>
		<comments>http://moms4mom.com/questions/5739/4-week-old-nursing-off-and-on-constantly-while-awake#comments</comments>
		<pubDate>Fri, 03 Sep 2010 17:37:46 +0000</pubDate>
		<dc:creator>Katooka</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://moms4mom.com/questions/5739/4-week-old-nursing-off-and-on-constantly-while-awake</guid>
		<description><![CDATA[<p>I have a 4 week old girl who I am breastfeeding. My issue is that during the day,... <a href="http://moms4mom.com/questions/5739/4-week-old-nursing-off-and-on-constantly-while-awake">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>I have a 4 week old girl who I am breastfeeding. My issue is that during the day, during her awake time, she is nursing a lot. She'll be awake for 2 or more hours and she'll nurse for 15 minutes, be happy for 10 minutes and then want to nurse again, repeat until she gets tired and I can get her to sleep. I'd love to be able to nurse her for 30-45 minutes solid and then have a solid time of not eating. I'm guessing this is just how she is but I thought I'd ask! </p>

        ]]></content:encoded>
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		</item>
		<item>
		<title>Do powers that grant allies melee basic attacks ignore positioning?</title>
		<link>http://rpg.stackexchange.com/questions/2191/do-powers-that-grant-allies-melee-basic-attacks-ignore-positioning</link>
		<comments>http://rpg.stackexchange.com/questions/2191/do-powers-that-grant-allies-melee-basic-attacks-ignore-positioning#comments</comments>
		<pubDate>Fri, 03 Sep 2010 17:28:41 +0000</pubDate>
		<dc:creator>MrHen</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://rpg.stackexchange.com/questions/2191/do-powers-that-grant-allies-melee-basic-attacks-ignore-positioning</guid>
		<description><![CDATA[<p>Do powers and effects that grant allies basic melee attacks allow those allies to take... <a href="http://rpg.stackexchange.com/questions/2191/do-powers-that-grant-allies-melee-basic-attacks-ignore-positioning">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>Do powers and effects that grant allies basic melee attacks allow those allies to take the attacks regardless of their positioning? In other words, if I attack with a Warlord's Commander's Strike:</p>

<blockquote>
  <p>Commander's Strike<br/>
  Melee weapon<br/>
  Target: One creature<br/>
  Attack: An ally of your choice makes a melee basic attack against the target<br/>
  Hit: Ally's basic attack damage + your Intelligence modifier</p>
</blockquote>

<p>And let my ally Rufus make a melee basic attack against the Zombie, does Rufus need to be within normal melee range of the Zombie? Or can Rufus make the attack from anywhere, since the power does not specify?</p>

<p>One of the player's in our group thinks that Rufus should get the attack regardless of positioning. The way I read this power is that I need to be within melee striking distance of the Zombie and Rufus needs to be within melee striking distance of the Zombie.</p>

<hr>

<p>A followup question is on powers that redirect or force attacks. Can a power that forces a monster to switch targets choose a new target that is outside of the original range? For example, if the Zombie attacks me with a melee attack and I redirect it to a Skeleton behind me, the Skeleton is beyond melee striking distance of the Zombie. What happens? Does the attack fizzle and nothing happens? Was it an illegal redirect? Does the attack still go through?</p>

        ]]></content:encoded>
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		<item>
		<title>The volume of an index</title>
		<link>http://money.stackexchange.com/questions/3392/the-volume-of-an-index</link>
		<comments>http://money.stackexchange.com/questions/3392/the-volume-of-an-index#comments</comments>
		<pubDate>Fri, 03 Sep 2010 16:57:56 +0000</pubDate>
		<dc:creator>user1473</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://money.stackexchange.com/questions/3392/the-volume-of-an-index</guid>
		<description><![CDATA[<p>http://yhoo.it/9K44hN lists the historical price of Dow Jones Industrial index in a... <a href="http://money.stackexchange.com/questions/3392/the-volume-of-an-index">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p><a href="http://yhoo.it/9K44hN" rel="nofollow">http://yhoo.it/9K44hN</a> lists the historical price of Dow Jones Industrial index in a table. The 6th column of this table is the volume information. What does the volume listed in thic column exactly represent?</p>

<p>For example, consider the following line from this table:</p>

<p>Sep 2, 2010 10,270.08   10,350.98   10,211.80   10,320.10   3,704,210,000   </p>

<p>The last number 3,704,210,000 is the volume information. What does it exactly represent?</p>

<p>Many thanks</p>

        ]]></content:encoded>
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		</item>
		<item>
		<title>What is the meaning of volume for an index?</title>
		<link>http://money.stackexchange.com/questions/3392/what-is-the-meaning-of-volume-for-an-index</link>
		<comments>http://money.stackexchange.com/questions/3392/what-is-the-meaning-of-volume-for-an-index#comments</comments>
		<pubDate>Fri, 03 Sep 2010 16:57:56 +0000</pubDate>
		<dc:creator>user1473</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://money.stackexchange.com/questions/3392/what-is-the-meaning-of-volume-for-an-index</guid>
		<description><![CDATA[<p>http://yhoo.it/9K44hN lists the historical price of Dow Jones Industrial index in a... <a href="http://money.stackexchange.com/questions/3392/what-is-the-meaning-of-volume-for-an-index">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p><a href="http://yhoo.it/9K44hN" rel="nofollow">http://yhoo.it/9K44hN</a> lists the historical price of Dow Jones Industrial index in a table. The 6th column of this table is the volume information. What does the volume listed in this column exactly represent?</p>

<p>For example, consider the following line from this table:</p>

<pre><code>Date        | Open      | High      | Low       | Close     | Volume
Sep 2, 2010 | 10,270.08 | 10,350.98 | 10,211.80 | 10,320.10 | 3,704,210,00
</code></pre>

<p>The last number 3,704,210,000 is the volume information. What does it exactly represent?</p>

        ]]></content:encoded>
			<wfw:commentRss>http://money.stackexchange.com/questions/3392/what-is-the-meaning-of-volume-for-an-index/feed/</wfw:commentRss>
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		<item>
		<title>Mostowski collapses and universal extensional relational classes</title>
		<link>http://mathoverflow.net/questions/37639/mostowski-collapses-and-universal-extensional-relational-classes</link>
		<comments>http://mathoverflow.net/questions/37639/mostowski-collapses-and-universal-extensional-relational-classes#comments</comments>
		<pubDate>Fri, 03 Sep 2010 16:49:39 +0000</pubDate>
		<dc:creator>Martin Brandenburg</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://mathoverflow.net/questions/37639/mostowski-collapses-and-universal-extensional-relational-classes</guid>
		<description><![CDATA[<p>In the following, by a relational class I mean a pair$^1$ $(A,R)$, where $A$ is a... <a href="http://mathoverflow.net/questions/37639/mostowski-collapses-and-universal-extensional-relational-classes">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>In the following, by a relational class I mean a pair$^1$ $(A,R)$, where $A$ is a class and $R \subseteq V \times V$ is a class relation, such that $R$ is well-founded and set-like on $A$ ($R$ is not assumed to be extensional). Homomorphisms of such classes are defined in the obvious way. Let $G : (A,R) \to (M,\in)$ be the Mostowski collapse of $(A,R)$, i.e. $G(x) = \{G(y) : y \in A , y R x\}$. Is this a functorial construction?</p>

<p>So let $f : (A,R) \to (A',R')$ a homomorphism, does this induce a homomorphism $(M,\in) \to (M',\in)$, such that the obvious diagram commutes? For this we have to check $G(x)=G(y) \Rightarrow G'(f(x))=G'(f(y))$ for all $x,y \in A$. Is this true?</p>

<p>If this works out fine and $R'$ is extensional, then $f$ extends to a homomorphism $(M,\in) \to (A',R')$. Is this extension unique? If yes, we have found a functor which is left-adjoint to the forgetful functor from relational classes to extensional classes.</p>

<p>If this does not work out, what about adding the assumption of transitivity? And if this also does not work, is there nevertheless some left-adjoint, which is then different from the Mostowski collapse?</p>

<p>$^1$ In $ZF$ we can't define pairs of classes, and perhaps the categories above are not well-defined. This does not affect the content of my question, which can be translated to a well-formed statement in $ZF$.</p>

        ]]></content:encoded>
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		</item>
		<item>
		<title>Distinguishing finitary permutation groups by action on tuples</title>
		<link>http://mathoverflow.net/questions/37638/distinguishing-finitary-permutation-groups-by-action-on-tuples</link>
		<comments>http://mathoverflow.net/questions/37638/distinguishing-finitary-permutation-groups-by-action-on-tuples#comments</comments>
		<pubDate>Fri, 03 Sep 2010 16:46:48 +0000</pubDate>
		<dc:creator>Colin Reid</dc:creator>
				<category><![CDATA[.SE SITE QUESTIONS]]></category>

		<guid isPermaLink="false">http://mathoverflow.net/questions/37638/distinguishing-finitary-permutation-groups-by-action-on-tuples</guid>
		<description><![CDATA[<p>Let $G$ and $H$ be permutation groups on the natural numbers such that the orbits of... <a href="http://mathoverflow.net/questions/37638/distinguishing-finitary-permutation-groups-by-action-on-tuples">See more</a></p>]]></description>
			<content:encoded><![CDATA[
            <p>Let $G$ and $H$ be permutation groups on the natural numbers such that the orbits of $G$ and $H$ are all finite.  Suppose that for all $\pi \in Sym(\mathbb{N})$, there is some $N$ (depending on $\pi$) such that for all $n \ge N$, the ordered tuple $(\pi(1),\pi(2),\dots,\pi(n))$ has a larger orbit (by a fixed ratio) under $G$ than it has under $H$.</p>

<p>Can $G$ and $H$ be conjugate in $Sym(\mathbb{N})$?</p>

<p>It would seem strange if this happened, but I can't think of an invariant that would definitively distinguish $G$ from $H$.</p>

<p>What if $G$ only has finitely many orbits of size $n$ for each $n \in \mathbb{N}$?  This would at least ensure that $G$ cannot be conjugate to one of its own subgroups.</p>

        ]]></content:encoded>
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