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Universal Method to Sort Complex Information Found

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Re: Universal Method to Sort Complex Information Found

#31

Post by DonaldFisk »

buckminster wrote: post #27
saganus wrote: post #18

Earlier quoted context omitted.

Why is it illegal and how do they enforce it? I know that something similar happens with airplane tickets but they get you with the luggage and with terms & conditions AFAIK. How is it similar/different with train tickets?

It is illegal because the railway byelaws make it illegal. The railway doesn't just have its own law, it also has its own police force, The British Transport Police, though as far as I know they don't do the ticket enforcement. You are not allowed to break a journey either, so a ticket inspector can spot a ticket for a longer journey at one end of the other. The multiple tickets ruse is more of a grey area.

BREAK OF JOURNEY

Rules vary by train company and route. In general you cannot break your outward journey (except for necessary changes of train) but you can break your return journey.

Source: https://www.splityourticket.co.uk/info/fare-types.aspx

I've already dealt with the legality of split ticketing in another post.

Re: Universal Method to Sort Complex Information Found

#32

Post by DoctorOetker »

ilyaraz1990 wrote: post #20
ttul wrote: post #17

Earlier quoted context omitted.

I await this paper with eager anticipation.

This is the second paper, where we present an actual fast algorithm for general normed spaces: https://ilyaraz.org/static/papers/daher.pdf . Enjoy!

thank you very much!

Re: Universal Method to Sort Complex Information Found

#33

Post by yorwba »

novia wrote: post #30
fizx wrote: post #19

Earlier quoted context omitted.

One assumes its an extension of their previous work ( https://arxiv.org/pdf/1501.01062.pdf ), which was only valid for Euclidian and Hamming spaces? Edit: The author says its https://ilyaraz.org/static/papers/daher.pdf , but he got marked dead by HN.

I vouched for the author's comment. Any clue why people are downvoting/flagging it?

New accounts posting comments with links are killed by the spam filter before anyone even gets the chance to downvote/flag.

Re: Universal Method to Sort Complex Information Found

#34

Post by gumby »

bunderbunder wrote: post #23
gumby wrote: post #10

Earlier quoted context omitted.

Really?? Is that true only when there are multiple paths between A & B or is there something else involved?

Chicago has a minor version of this, even without zone fares: The entry fee to get on a train is $2.50 everywhere except O'Hare Airport, where it's $5.

Interesting, thanks!

Re: Universal Method to Sort Complex Information Found

#35

Post by tzs »

gumby wrote: post #10
sshine wrote: post #5

Earlier quoted context omitted.

Incidentally, the zone system for the Danish public transit system is not a metric space. (The ticket you need from A to B is not necessarily the same as from B to A.) That's a kind of practical graph where you want efficient shortest path algorithms for.

Really?? Is that true only when there are multiple paths between A & B or is there something else involved?

Another possibility is that there is more demand in one direction.

You might have a major city, A, a center of finance and law and full of corporate headquarters, and a smaller city, B, where many of the companies whose headquarters are in A have their engineering and manufacturing facilities.

Someone making a deal with one of those companies may need to visit both engineering to work out technical details first and then visit headquarters to work out business, financial, and legal details. They will travel from home to B, and then travel to A, and then when done travel directly home from A. This may happen much more than the other direction--people needing to visit headquarters first and then going to visit engineering and manufacturing, without needing to go back to headquarters.

Net result: more passengers needing B to A than A to B. This can result in A to B trips having empty seats. It might even result in some trips with no passengers at all! They can't simply cancel those trips, because they need to get the vehicles to B to handle the B to A traffic, so they sell seats cheap.

Re: Universal Method to Sort Complex Information Found

#36

Post by tlb »

DoctorOetker wrote: post #13
bunderbunder wrote: post #4

Earlier quoted context omitted.

It's a rather large set, but it's got some noteworthy holes. Cosine distance, for example.

my gut feeling tells me - ln((1+Similarity_cosine(A,B))/2) would satisfy the triangle inequality.

It produces negative distances, which disqualifies it as a metric.

Re: Universal Method to Sort Complex Information Found

#38

Post by Lewton »

gumby wrote: post #10
sshine wrote: post #5

Earlier quoted context omitted.

Incidentally, the zone system for the Danish public transit system is not a metric space. (The ticket you need from A to B is not necessarily the same as from B to A.) That's a kind of practical graph where you want efficient shortest path algorithms for.

Really?? Is that true only when there are multiple paths between A & B or is there something else involved?

They use a zone system, and you don’t have to pay for a zone if you get off at the first stop after entering it.

This creates the asymmetry

Re: Universal Method to Sort Complex Information Found

#39

Post by notyourwork »

bunderbunder wrote: post #23
gumby wrote: post #10

Earlier quoted context omitted.

Really?? Is that true only when there are multiple paths between A & B or is there something else involved?

Chicago has a minor version of this, even without zone fares: The entry fee to get on a train is $2.50 everywhere except O'Hare Airport, where it's $5.

The tourist fee.
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