1. [OT] How many integers?
- Posted by Matt Lewis <matthewwalkerlewis at yahoo.com> Jun 09, 2003
- 352 views
rforno at tutopia.com wrote: > You know, the set of *all* integers (abstract integers, not > Euphoria nor C nor computer integers) is infinite, but larger than > the set of *even* integers, that is also infinite. Actually, the set of even integers (let's call it ZE) and the set of all integers (Z) are the same size (countably infinite). The standard way to prove this is to use some function to map from one set to the other, showing that there is the sets map each other completely with a one-to-one relationship (bijective): Then for any z in Z, there is a ze in ZE such that z = ze / 2. In other words, for any normal integer, I can use even integers to 'count' the normal integers, and so the sets must be the same size (btw, the set of rational numbers is the same size, but any interval of real numbers will be bigger). Matt Lewis
2. Re: [OT] How many integers?
- Posted by Igor Kachan <kinz at peterlink.ru> Jun 09, 2003
- 349 views
Hello Matt: > > rforno at tutopia.com wrote: > > You know, the set of *all* integers (abstract integers, not > > Euphoria nor C nor computer integers) is infinite, but larger than > > the set of *even* integers, that is also infinite. > > Actually, the set of even integers (let's call it ZE) and the set of all > integers (Z) are the same size (countably infinite). The standard way > to prove this is to use some function to map from one set to the other, > showing that there is the sets map each other completely with a > one-to-one relationship (bijective): > > Then for any z in Z, there is a ze in ZE such that z = ze / 2. In other > words, for any normal integer, I can use even integers to 'count' the > normal integers, and so the sets must be the same size (btw, the set of > rational numbers is the same size, but any interval of real numbers will > be bigger). > > Matt Lewis I say, Russian is better for such the things We say "power of a set", not "size of a set". Regards, Igor Kachan kinz at peterlink.ru
3. Re: [OT] How many integers?
- Posted by Igor Kachan <kinz at peterlink.ru> Jun 09, 2003
- 348 views
Hello again Matt: > > rforno at tutopia.com wrote: > > You know, the set of *all* integers (abstract integers, not > > Euphoria nor C nor computer integers) is infinite, but larger than > > the set of *even* integers, that is also infinite. > > Actually, the set of even integers (let's call it ZE) and the set of all > integers (Z) are the same size (countably infinite). The standard way > to prove this is to use some function to map from one set to the other, > showing that there is the sets map each other completely with a > one-to-one relationship (bijective): > > Then for any z in Z, there is a ze in ZE such that z = ze / 2. In other > words, for any normal integer, I can use even integers to 'count' the > normal integers, and so the sets must be the same size (btw, the set of > rational numbers is the same size, but any interval of real numbers will > be bigger). Then, Russians say "multitude" or "host", not "set". So, "power of the normal integers host" forces to think about infinity first of all. And "host" itself may be small - as "set" is something small first of all. Russian is good for such the things, isn't it? Regards, Igor Kachan kinz at peterlink.ru
4. Re: [OT] How many integers?
- Posted by Igor Kachan <kinz at peterlink.ru> Jun 09, 2003
- 342 views
Hello Matt: > Igor Kachan wrote: > > > I say, Russian is better for such the things > > We say "power of a set", not "size of a set". > > If I were being correct, I really should have said > the "cardinality of the set." > To my [native speaking american-english] ear, "size" > sounds better than "power". > (Plus my "proof" actually contains a lot of hand > waving that might not be clear to someone not > familiar with set theory.) > ...and then Igor wrote: > > Then, Russians say "multitude" or "host", not "set". > > So, "power of the normal integers host" forces to think > > about infinity first of all. > > And "host" itself may be small - as "set" is something > > small first of all. > > "Power of the normal integers host" sounds like you're > talking about an army or something to me. :) Ok, try "Power of the normal integers multitude" > Then again, the "power of the host" of > Russian words I know is a very small number. What a problem? Learn Russian and you'll be all set. Do you see that famous "set" again? "multitude" is much more clear term for this subject. Russian is Russian, no? > > Russian is good for such the things, isn't it? Do you see Russian is really good? > Well, I've heard that you guys have some pretty sharp > mathematicians, so I won't disagree with you > (though IMHO it was a Frenchman who was probably the > greatest pioneer in this area--Cauchy--so I wonder > what the French would say?). This is a German source, Cantor's theory, he was the first setman-hostman-multitudeman > Guess it's another case of imperfect translations. Yes, my "host", "power", "multitude" are just the reverse translation of that Cantor's theory terms from Russian into English. > I still like english, BTW. :p > > Matt Lewis Ok, and I still like Russian, BTW. :b Regards, Igor Kachan kinz at peterlink.ru