Search found 102 matches

by DavidSh
Fri Apr 27, 2018 3:59 pm UTC
Forum: Mathematics
Topic: Name of Rounded Triangle
Replies: 8
Views: 1894

Re: Name of Rounded Triangle

Three sets of foci, but six ellipses. Let the rope have length L. Let the poles be A, B, and C, forming a triangle with sides of length d(A,B), d(B,C), d(C,A). Suppose L is only slightly longer than d(A,B)+d(B,C)+d(C,A). The elliptical arc near side AB contains points x such that d(x,A)+d(x,B) = L-(...
by DavidSh
Fri Apr 27, 2018 3:39 pm UTC
Forum: Computer Science
Topic: Formally, What is P and NP?
Replies: 17
Views: 3526

Re: Formally, What is P and NP?

Not quite, no.

The comparison is between what Non-deterministic machines can do in polynomial time and what deterministic machines can do in polynomial time.
by DavidSh
Fri Apr 27, 2018 3:27 pm UTC
Forum: Mathematics
Topic: Name of Rounded Triangle
Replies: 8
Views: 1894

Re: Name of Rounded Triangle

The descriptions of this construction I can find on-line just call it an "Oval", which is a much broader term.
It consists of six elliptical arcs, not three.
by DavidSh
Wed Apr 25, 2018 9:23 pm UTC
Forum: Fictional Science
Topic: Yet another FTL question...
Replies: 35
Views: 4686

Re: Yet another FTL question...

I think the best answer is "nope". Under special relativity, all inertial frames are equivalent. Sure, in your reference frame you measure the clocks in the other reference frame as running slow, but, in the other reference frame they measure the clocks in your reference frame as running s...
by DavidSh
Fri Apr 20, 2018 4:50 pm UTC
Forum: Computer Science
Topic: Formally, What is P and NP?
Replies: 17
Views: 3526

Re: Formally, What is P and NP?

1) Your understanding of NP is incorrect. It is "polynomial-time on a non-deterministic Turing machine", not "non-polynomial". The set of problems in P is a subset of the set of problems in NP. The classic question is, are there any problems in NP that aren't also in P? 2) A typi...
by DavidSh
Mon Apr 16, 2018 9:51 pm UTC
Forum: Mathematics
Topic: Projecting a Polytope
Replies: 5
Views: 1155

Re: Projecting a Polytope

I don't expect this to be easy. After all, if y is of dimension 1 you basically have Linear Programming (finding a maximum or minimum of a linear function over a region defined by linear inequalities), which took quite some time for somebody to find a polynomial-time algorithm for.
by DavidSh
Tue Apr 10, 2018 12:50 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1973: "Star Lore"
Replies: 33
Views: 4722

Re: 1973: "Star Lore"

I had always assumed the theatrical / motion picture "gaffer" as being a dialect form of "grandfather", being used in the sense of "old man". As opposed to the "best boy", his chief assistant. I never actually looked for evidence on this, though.
by DavidSh
Fri Apr 06, 2018 1:48 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1976: "Friendly Questions"
Replies: 35
Views: 4687

Re: 1976: "Friendly Questions"

For a moment I thought scharb was claiming to be over 200 years old.
by DavidSh
Mon Apr 02, 2018 12:44 pm UTC
Forum: Serious Business
Topic: Census Dickery
Replies: 59
Views: 6890

Re: Census Dickery

. The Constitution is actually really clear on that. If it means Citizens, it says Citizens. If it means person, it says Person. All Citizens are Persons, but not all Persons are Citizens. Both are distinct terms with different legal definitions, but the main takeaway is that a person is just some ...
by DavidSh
Sat Mar 31, 2018 1:22 pm UTC
Forum: Hardware
Topic: Thicker Extension Cord = Blown Fuses
Replies: 4
Views: 1858

Re: Thicker Extension Cord = Blown Fuses

What voltage are you using? Power is voltage times current, so if you need to draw 1800 watts at 120 volts, you need 15 amps of current. Adding another 100 watts for the pump pushes you up to nearly 16 amps. If your voltage is below 120 volts, you need more current. If you are working at 220 volts, ...
by DavidSh
Fri Mar 23, 2018 5:13 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1971: "Personal Data"
Replies: 82
Views: 8186

Re: 1971: "Personal Data"

Stargazer71 wrote:So I’m pretty sure that Randall is being sarcastic about the limits of his own knowledge in the second panel ...


I don't think Randall is saying anything at all about his own knowledge in the second panel, even sarcastically,
by DavidSh
Sat Mar 03, 2018 12:09 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1937: "IATA Airport Abbreviations"
Replies: 63
Views: 7462

Re: 1937: "IATA Airport Abbreviations"

Just as well LDY now calls itself the City Of Derry Airport. Londonderry Airport could get confused for London Derry Airport.
by DavidSh
Thu Mar 01, 2018 7:57 pm UTC
Forum: The Help Desk
Topic: PyPI [resolved]
Replies: 8
Views: 2707

Re: PyPI

What do you get from dir(labmath) after you have imported it?
by DavidSh
Thu Feb 22, 2018 6:32 pm UTC
Forum: Movies and TV Shows
Topic: Modern movies to blow 50's directors' minds
Replies: 186
Views: 38326

Re: Modern movies to blow 50's directors' minds

Films with all-black or nearly all-black casts were nothing new in the 1950s. There had been an entire class of "race films", and also major works like Stormy Weather(1943) and Carmen Jones(1954).
by DavidSh
Fri Feb 09, 2018 12:52 am UTC
Forum: General
Topic: How did a discontinued foreign coin end up in my car?
Replies: 42
Views: 4588

Re: How did a discontinued foreign coin end up in my car?

To get from the US to any part of France, it would either have to drive on water, or travel as freight. (There is not a continuous road from the US to French Guiana, and no car ferry to St. Pierre & Miquelon from anywhere.)
by DavidSh
Fri Feb 09, 2018 12:41 am UTC
Forum: Religious Wars
Topic: stop walking on the escalators
Replies: 104
Views: 30832

Re: stop walking on the escalators

It's a little more complicated than that, because people might be packed closer together on the escalator than most people are comfortable when walking. Outside of certain fraternity traditions.
by DavidSh
Sun Feb 04, 2018 6:47 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13396
Views: 1434191

Re: Lucky Ten Thousand (TIL)

... I'm not sure there are any dialects where stalk = stark, but in my dialect the vowels of stalk and stark are the same and the only difference is whether there's an r sound. (For me, stalk = stock = /stɑːk/ (f a ther/sp a vowel), which I think is the same as British "stark"; stark = /s...
by DavidSh
Fri Feb 02, 2018 3:16 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13396
Views: 1434191

Re: Lucky Ten Thousand (TIL)

It would be better if we all used and understood IPA. English-speakers from different parts of the world pronounce 'r' differently. I suspect SecondTalon is rhotic, while Mutex is non-rhotic. I had thought south-west England still had holdouts that pronounced "Arr" differently from "A...
by DavidSh
Wed Jan 31, 2018 6:41 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1949: "Fruit Collider"
Replies: 54
Views: 4983

Re: 1949: "Fruit Collider"

I have actually seen fruit labelled "Apple Bananas" in the store, and I have heard about "Strawberry Guavas", so both of these are presumed stable.

On the other hand, "Strawberry Rhubarb" can serve as pie filling, but is not stable as a standalone fruit.
by DavidSh
Wed Jan 31, 2018 2:21 pm UTC
Forum: General
Topic: How did a discontinued foreign coin end up in my car?
Replies: 42
Views: 4588

Re: How did a discontinued foreign coin end up in my car?

I know I keep coins from old foreign trips. Occasionally they work themselves back into my pockets. If you or your father ever gave a ride to somebody else with such a coin, it could have fallen out of a pocket. Also note that, before the Euro, Francs were also in use in the French islands in the Ca...
by DavidSh
Mon Jan 29, 2018 6:49 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1948: "Campaign Fundraising Emails"
Replies: 34
Views: 4383

Re: 1948: "Campaign Fundraising Emails"

Pleasantly surprised to see the Tolkien quote there. I don't see how it would work as a request for money, though.
by DavidSh
Wed Jan 24, 2018 4:02 pm UTC
Forum: News & Articles
Topic: Where Aren't They Now (Obituaries)
Replies: 234
Views: 43236

Re: Where Aren't They Now (Obituaries)

I was momentarily confused on hearing this on the radio this morning, since it sounded like they were announcing the death of an "Ursula Kayler-Guin". We read The Dispossessed in our book club, but I'm pretty sure that was under the name Ursula Le Guin. Did she start using the "K.&qu...
by DavidSh
Mon Jan 22, 2018 3:29 pm UTC
Forum: News & Articles
Topic: Winfrey presidency
Replies: 156
Views: 12159

Re: Winfrey presidency

Objectively speaking, Trump is both taller and heavier than Winfrey today. He weighs about the same as Winfrey at her heaviest, though his BMI is less than hers was. So "Go big" could be taken as "Go with Trump".

In case this helps.
by DavidSh
Tue Jan 16, 2018 1:49 pm UTC
Forum: Mathematics
Topic: PI - Invention or Discovery
Replies: 88
Views: 7618

Re: PI - Invention or Discovery

I seem to remember an Isaac Asimov robot story, that included a robot that refused to believe that it was created by humans, because it felt itself obviously superior to them.
by DavidSh
Fri Jan 12, 2018 10:22 pm UTC
Forum: Mathematics
Topic: PI - Invention or Discovery
Replies: 88
Views: 7618

Re: PI - Invention or Discovery

At least two of the claims in that patent refer to "exclusively ORing": 10. In a graphic display system of the type in which a display is generated corresponding to the contents of a memory storing an image as a first set of data each representing an element of that stored image, the impro...
by DavidSh
Fri Jan 12, 2018 12:49 am UTC
Forum: Fictional Science
Topic: Yet another FTL question...
Replies: 35
Views: 4686

Re: Yet another FTL question...

I'm probably repeating what a previous poster has said, but I'll continue anyway. If the path from one event A in spacetime to another event B is faster-than-light, then they have "space-like" separation. From some inertial frames, A occurs before B. From other inertial frames, B occurs be...
by DavidSh
Tue Jan 09, 2018 1:57 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1939: "2016 Election Map"
Replies: 55
Views: 7013

Re: 1939: "2016 Election Map"

He did say he is trying to keep national totals intact. It would be surprising if using the same rounding point for all parties would achieve that. Can you determine if there is a consistent rounding point within each party?
by DavidSh
Thu Jan 04, 2018 3:15 pm UTC
Forum: General
Topic: Instant Runoff vs. Approval Voting
Replies: 10
Views: 3990

Re: Instant Runoff vs. Approval Voting

Intellectually, I like a method where (1) Everybody ranks the options from best to worst, allowing for declaring subsets of options as equivalent, as: A, B, {C, D, E}, F, meaning A is preferred to anything else, B is preferred to anything besides A, no preference among C, D, and E, and finally, F is...
by DavidSh
Mon Dec 18, 2017 7:20 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1930: "Calendar Facts"
Replies: 32
Views: 4354

Re: 1930: "Calendar Facts"

I'd think the Libation of the Mason-Dixon Line (the Pennsylvania-Maryland border, in part), would be Rye Whiskey.
Of the Prime Meridian, Gin.
by DavidSh
Mon Dec 18, 2017 5:47 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1930: "Calendar Facts"
Replies: 32
Views: 4354

Re: 1930: "Calendar Facts"

Treating this as "Did you know <fact 1>? Apparently, <fact 2>.", I wonder how many of the branches can be traversed with paths where both facts are true. I'm having difficulty working the Mason Dixon Line into anything meaningful. It isn't part of any time zone boundaries.
by DavidSh
Sun Dec 10, 2017 7:03 pm UTC
Forum: Mathematics
Topic: How to prove that End(V) is a k-algebra
Replies: 2
Views: 1563

Re: How to prove that End(V) is a k-algebra

If you need to prove that something is a vector space, you need to give serious consideration as to the underlying field.
by DavidSh
Mon Dec 04, 2017 9:31 pm UTC
Forum: Science
Topic: Fish Base is a Thing that Exists
Replies: 12
Views: 1787

Re: Fish Base is a Thing that Exists

I figured it was part of the Extended Rules for baseball.
by DavidSh
Mon Nov 27, 2017 9:42 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1921: "The Moon and the Great Wall"
Replies: 8
Views: 2109

Re: 1921: "The Moon and the Great Wall"

It seems to me like you are missing the obvious, if obsolete, meaning of "Celestial", as pertaining to Imperial China.
by DavidSh
Fri Nov 24, 2017 8:32 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13396
Views: 1434191

Re: Lucky Ten Thousand (TIL)

Does anybody besides that one anonymous Wikipedia editor make the claim that the composer and the Navy general are the same man? The version of the article that makes this claim has only been up a week or two, but the usual response on Wikipedia of that kind of language "there are reasons to be...
by DavidSh
Tue Nov 21, 2017 8:09 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1916: "Temperature Preferences"
Replies: 82
Views: 8735

Re: 1916: "Temperature Preferences"

PinkShinyRose wrote: The Western Europe doesn't have significant earthquakes, tsunamis or significant hurricanes. We do have a coastal climate with the temperature varying by latitude.


I understand Lisbon had a big earthquake once, but it was quite some time ago.
by DavidSh
Mon Nov 13, 2017 4:50 pm UTC
Forum: Mathematics
Topic: Maximizing 2 Variables
Replies: 19
Views: 3062

Re: Maximizing 2 Variables

I think the late Dr. Hardin was speaking in general terms, that you can't always maximize both of two inter-related variables. Of course there are specific cases in which you can. Just like saying you can't trisect an angle with a compass and straight-edge, while there are specific angles that you c...
by DavidSh
Mon Nov 06, 2017 10:52 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13396
Views: 1434191

Re: Lucky Ten Thousand (TIL)

But a properly functioning TARDIS can look like just about anything, can't it, at least on the outside?
by DavidSh
Wed Oct 25, 2017 7:55 pm UTC
Forum: Mathematics
Topic: What is a Euclidean Number
Replies: 13
Views: 3134

Re: What is a Euclidean Number

I think they mean the following vaguely algorithmic process: Start with S= the set of all natural numbers (include 0). These can all be constructed with compass and ruler, given a unit length. Repeat forever: Pick a, b, and c from S. Let x be a solution to ax^2 + bx + c = 0. (Found using the quadrat...
by DavidSh
Fri Oct 13, 2017 7:33 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1127: "Congress"
Replies: 446
Views: 73419

Re: 1127: "Congress"

Am I the first person to notice that the axis for the senate is mislabeled? On the right, it goes 0-10-20-30-40-50- 40-40 -80. No, you are not. Somebody else commented on this, a few pages in, but before the thread turned into the longstanding debate about libertarianism/anarchism. I'm not willing ...
by DavidSh
Fri Oct 13, 2017 3:35 pm UTC
Forum: General
Topic: Thoughts for ships
Replies: 89976
Views: 7578606

Re: Thoughts for ships

I don't understand why you all are so concerned about Service Control Points.

(That's the standard meaning of SCP among telcos.)

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