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Comment author: eternal_neophyte 16 March 2015 12:11:37AM 2 points [-]

I don't think any solution to it would necessarily reveal any major new insights.

I'll just leave this here: http://math.stackexchange.com/questions/1892/the-practical-implication-of-p-vs-np-problem

Comment author: jkaufman 17 March 2015 05:26:02PM 0 points [-]

I mostly agree with passve_fist:

  • A problem can be in P and still not be computationally feasible; O(n^10000) algorithms are still in P.
  • Almost always a very good approximate answer is good enough. The travelling salesman problem is in NP, but we have efficient enough approximations (not just in P, but small exponents) that the benefit of getting to perfect is low.
Comment author: jkaufman 11 March 2015 04:26:29PM 9 points [-]

Prediction: people who aren't Harry can use the stone once every 216 seconds (3:36).

(The idea being that the rule is "400 times a day" and Harry has a 26hr day.)

Comment author: Unknowns 10 March 2015 07:23:35PM 14 points [-]

Time Turners use units of one hour, so at least some kinds of magical items use our units.

Comment author: jkaufman 11 March 2015 01:21:16PM 1 point [-]

Can you use the time turner in different increments, and possibly with a different maximum, if you fully understand hours are arbitrary? This sounds exactly like partial transfiguration.

(Alternatively, you go back some fixed amount of time for every grain of time sand in the turner, and you could build one of other increments by using a different quantity of sand.)

Comment author: qsz 04 March 2015 12:24:55PM *  6 points [-]

There was a good discussion on LW about Arthur Chu's performance on Jeopardy LINK - especially how he took advantage of regular patterns underlying question selection and "random" events to try and maximise his winnings.

The comment thread on that discussion also mentions other "rationalist" practices by other contestants.

Comment author: jkaufman 06 March 2015 04:45:27PM 3 points [-]

Note that Arthur does not consider himself a rationalist, and hates LW.

Comment author: jkaufman 02 March 2015 02:34:34AM *  3 points [-]

Harry can do a lot of things, but V already knows many of them. His strongest options are things he's sure V has no idea he can do, like the swerving hex he used on Moody.

EDIT: His strongest options for ways to outwit LV, not things to tell LV to save friends.

Comment author: Izeinwinter 26 February 2015 03:48:11PM 0 points [-]

And since todays temp work was impressively mindless, I got rather a lot of thinking done.

Fair warning, this may well just be heading right into epileptic trees turf.

Dumbledore just cast himself from time in order to fulfill the prophecy about Harry Potter.

That line about how Harry will have to find some other dark lord to vanquish? It was not about the far future at all, it was about the next four minutes.

Let me explain: As long as the prophecy is in play, only Harry can defeat the dark lord. And that is not going to work against Voldemort. An 11 year old, no matter how resourceful and clever is just not going to come out on top of that fight. But just as the prophecy could have been about Neville as well as Harry, there is also more than one dark lord it could be about. The story pointed this out earlier.

So the prophecy is no longer in effect. Voldemort can be defeated by anyone with the firepower and a counter for the horcruxes.

And Dumbledore, the order of the pheonix, and everyone else he could bring in on it have crowdsourced a smackdown, which is about to land.

Most of this smackdown is in the form of longterm plots that are about to bear fruit.

From the top: Dumbledore knew who Quirrel and Harry were, from day one. Each and every single piece of information given to Harry was relayed in the expectation that Voldemort would hear it.

Dumble, Flamel, et all made a fake true cloak of invisibility. The point of this being to provide misinformation about what the mark of the deadly hallows looks like. I don't know what the "stone of resurrection" actually is, but I think Voldy will not like what it does, not one tiny bit. At a guess, it is for mapping out the magical "net" and find the darn things?

The people who just apparated in: Not death eaters. They're masked and cloaked minions. That's such a cliche it's actually painful to contemplate.

Voldemorts use of the stone to raise the dead is not the first time it has been used to do that. The rite he intended to use is not original to him, it is an old piece of lore, and it is an old piece of lore Flamel told the order of the phoenix about. This means "Flamel" has been able to raise anyone who still had foes and servants living and known graves of ancestors.

So it isn't new. Not widely used, but not new. Note that this isn't a good rite for defeating death in general, simply because most people dont have the first two at all. But it is a very effective way to ditch an identity for any of her collaborators who are in it for the long haul. Which means a lot of very powerful, supposedly deceased wizards and witches owe her. And he just tried to have her killed. (May even have succeeded. If so, she's probably already back up and wanting her stone back before anything expires.)

That is what the hour's delay in Snapes room was about - it was to take all the deatheaters into custody, and gather people up for a seriously onesided bout. The reason this ends in "liters of blood" is that the plan is to drain Voldemort dry so that they can raise as many of his victims as possible.

Oh, and Dumbledore didn't have unique access to divination, beyond a season pass to the hall of prophecies. That would make the plot unsolvable, because we can't reason a-causally.

Comment author: jkaufman 26 February 2015 08:11:17PM 0 points [-]

How does the fake Cloak hide you from the Mirror?

Comment author: MathMage 26 February 2015 06:20:02PM 1 point [-]

I am dubious that "seeking help from the Muggles" is as straightforward as you seem to think it is.

Comment author: jkaufman 26 February 2015 08:08:25PM 0 points [-]

Can't you Imperious a few heads of state?

(Though probably not, or someone would have done it, though McGonagall may be aware of the details of the restrictions.)

Comment author: jkaufman 26 February 2015 07:57:17PM 6 points [-]

Crazy thought: Merlin lives backwards, Dumbledore has the Line of Merlin Unbroken, Dumbledore has a weird way of being able to make the future happen for the wrong reasons, Dumbledore just vanished into a place beyond time. Which makes me think Dumbledore might be Merlin's origin.

Comment author: Desrtopa 25 February 2015 03:29:38PM 5 points [-]

For instance, Harry believes that the wizarding economy should be trivially exploitable via exchange with the Muggle precious-metals market. He believes this because even though he knows about half-bloods (i.e. witches and wizards who have a Muggle parent), he thinks that he is special and that nobody else ever would have thought of that.

Don't forget, his Occlumency teacher would mention after every session that he wished he would be allowed to remember the arbitrage trick.

Eliezer has talked about how one of his main reasons for writing the story as a work of fanfiction is that it gets the audience to accept a world that is massively exploitable by the main characters, which they would have thought was a case of the author making things too easy on them if the author had actually created it. Eliezer wrote a story set in the world of Harry Potter because Rowling didn't think very hard about the implications of her worldbuilding and created a massively exploitable setting.

Comment author: jkaufman 25 February 2015 04:27:29PM 1 point [-]

his Occlumency teacher would mention after every session that he wished he would be allowed to remember the arbitrage trick.

Which is also consistent with "Harry expects it to work and the teacher doesn't know much about finance".

Comment author: nydwracu 23 February 2015 03:52:55AM 1 point [-]

Scribbles over the mirror room? I'm asking why Baba Quirrellmort would want himself and Harry to show up as "Tom M. Riddle" on the map. (Which reveals to anyone who has the map that Q = V and H = V, which reveals the horcrux thing...)

Comment author: jkaufman 23 February 2015 04:12:24PM 1 point [-]

The map may not have shown that at other times. Dumbledore didn't remark on it when he asked "find Tom Riddle". ("Harry? You're Tom Riddle? WTF?) All we know is that the map currently says they're both Riddle.

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