reciprocal魔兽世界服务器维护
魔兽世界服务器维护 时间:2021-01-13 阅读:(
)
CURRICULUMINSPIRATIONS:www.
maa.
org/ciInnovativeOnlineCourses:www.
gdaymath.
comTantonTidbits:www.
jamestanton.
comWOW!
COOLMATH!
CURIOUSMATHEMATICSFORFUNANDJOYAPRIL2016PROMOTIONALCORNER:Haveyouanevent,aworkshop,awebsite,somematerialsyouwouldliketosharewiththeworldLetmeknow!
Iftheworkisaboutdeep,joyous,andrealmathematicaldoingI'llhappilymentionithere.
***Peopledomathvideos!
CheckoutMarcChamberlain'shttps://www.
youtube.
com/watchv=bCiQOwP4LrY.
WhydoesworkTHISMONTH'SPUZZLER:Itispossibletocolorthefirsteightcountingnumberseacheitherredorbluesothatweneverhavethreedistinctintegers,,andallthesamecolor.
CanthesametaskbecompletedwiththefirstninecountingnumbersWhatisthesmallestsothateverycoloringofthenumbers1,2,3,…,eitherredorblueissuretohaveamonochromatictripleHowdoestheanswerchangeifwepermitgeneric"triples"with(Nowweneedeachandtobedistinctcolorstoo.
)JamesTanton2016www.
jamestanton.
comandwww.
gdaymath.
comRAMSEYTHEORYHereisaclassicresult:Ifsixuniversitystudentsareselectedatrandom,thenthereissuretobeeitherthreestudentsamongthesixwhoaremutualfriendsorthreestudentswhoaremutualstrangers(orboth).
(Weareassumingherethatfriendshipisreciprocal:IfAlbertisfriendswithBilbert,thenBilbertisalsofriendswithAlbert.
Beingastrangerisreciprocaltoo.
)Here'sthereasoning:Chooseoneofthesixstudents,Cuthbert.
Therearefiveotherstudentseachofwhichheiseitherfriendswithorastrangerto.
SupposeCuthbertisfriendswithamajorityofthesefive,thatis,friendswithatleastthreeofthem.
(If,instead,heisastrangertoamajority,thenswitchthewordsfriendandstrangerinwhatfollows.
)Amongthesethreepeople,ifanytwoaremutualfriends,thenwehaveatripleoffriends:Cuthbertandthosetwo.
Ifnoneofthosethreearefriends,thenwehavefoundatripleofstrangers.
Theresultisnottrueforjustfivepeopleselectedatrandomasseenbythisgraphic.
Hereeachdotrepresentsastudentandarededgeindicatesmutualfriendsandablueedgemutualstrangers.
Nothreepeopleareconnectedbyedgesallofthesameonecolor.
Intermsofcoloreddiagrams,ourpartyresulttranslatesasfollows:Drawsixdotsonapageandthe15edgesbetweenallpossiblepairsofdots.
Itisimpossibletocolorthoseedgesredandblueandavoidamonochromatictriangle.
Togeneralizethisidealetdenotetheleastnumberofdotsoneneedstodrawonapagesothatifweconnectallpairsofdotswitheitherredorblueedges,thereissuretobeeitherasetofdotswithalltheedgesamongthemredorasetofdotswithalltheedgesamongthosedotsblue.
(Thisisassumingthatsuchaleastnumberexists!
Maybenomatterhowmanydotsonedrawsonecanalwaysavoidred"cliques"ofsizeandbluecliquesofsize)Theideaofstudyingthenecessarysizeofasystemtoensurecertainsub-substructuresexistswasfirstformallyexploredbyBritishmathematicianFrankRamsey(1903–1930).
ThisworkistodaycalledRamseyTheoryinhishonor.
Ourpartyresultreadsas.
(Drawsixdotsandcolortheedgesbetweenthenredandblue.
Eitheraredtriangleissuretoappearorablueone.
)Itisnothardtoseethat.
(Ifwedrawdotsonapageandcolortheedges,theneitheroneisredandwe'vefoundredcliqueofsizeoralledgesareblueandwehaveabluecliqueofsize.
Also,isnotorsmaller:coloringalltheedgesbetweendotsblueillustratesthis.
)JamesTanton2016www.
jamestanton.
comandwww.
gdaymath.
comComputingRamseynumbersisstillaveryactiveareaofresearch.
Onlythesefewvaluesarecurrentlyknown.
(Ofcourse,:justswitchcolors.
)Generalizing…Setastheleastnumberofdotsoneneedstodrawonthepagetoensurethat,incoloringtheedgesred,blueandgold,eitheracliqueofdotswithnothingbutrededgesbetweenthem,oracliqueofdotswithnothingbutblueedgesbetweenthem,oracliqueofdotswithnothingbutgoldedgesbetweenthemissuretoappear.
Itisknownthat.
(Draw17dotsonapageandcoloreachofthe153edgesbetweenthemeitherred,blue,orgold.
Thenamonochromatictriangleissuretoappear.
Also,itispossibletoavoidmonochromatictriangleswithonly16dotsonthepage.
)Andforfullgeneralitysetastheleastnumberofdotsoneneedstodrawonapagesothat,incoloringeachoftheedgesbetweenapairofdotsoneofcolors,thereissuretobeacliqueofdotswithalltheedgesbetweenthemthethcolor,forsome.
Ofcourse,weareassumingthatthisnumberexists-thatthereisaleastnumberofdotsthatassuresamonochromaticstructureappears.
Ramsey'sTheorem:Eachisindeedameaningfulfinitenumber.
Let'sillustratewhy.
ThevaluedoesnotappearonthelistofknownRamseynumbers.
Butwecanprovethatitisafinitenumber.
Wehave,fromthelist,and.
Drawdotsonthepageandcolortheedgesbetweenthemredandblue.
Weshallnowreasonthateitheracliqueofdotsexistswithalledgesbetweenthemredoracliqueofdotsexistswithalledgesbetweenthemblue.
Thiswillestablishthat.
Inourdiagramofdotswithedgescolored,chooseoneparticulardot.
CallitDilbert.
Dilberthassomerededgesemanatingfromitconnectingitto,say,otherdots.
TheremainingedgesemanatingfromDilbertareblue,connectingtootherdots,say.
Here.
Nowitcan'tbethatbothand.
Soeitherisatleastorisatleast.
Case:ConsiderthedotsthatconnecttoDilbertbyrededges.
Becausethereiseitheraredcliqueofamongthesedotsorthereisbluecliqueofamongthem.
Ifthereisaredcliqueof3,thenincludingDilbertintheclique(alledgestoDilbertarered)actuallymeanswehavearedcliqueof,oneofthetwostructureswearehopingtoseefor.
If,ontheotherhand,thereisabluecliqueof,thenwehaveabluecliqueof!
Eitherwaywehavefoundoneofthetwothingswearelookingfor.
JamesTanton2016www.
jamestanton.
comandwww.
gdaymath.
comCase:ConsiderthedotsthatconnecttoDilbertviablueedges.
Because,amongthesedotsthereiseitheraredcliqueof(oneofthepossibilitieswewerehopingfor)orabluecliqueof.
Inthelattercase,sincealltheedgestoDilberthereareblue,addingDilberttothecliqueoffiveactuallymakesabluecliqueof!
Again,wearesuretohaveatleastoneofthetwostructureswewerelookingfor.
Ingeneral,onecanprovejustthiswaytheinequality:.
ThenfromknowingthatRamseynumberswithsmallerindicesarefinitewecanreasonthateveryRamseynumberisfinite.
GeneralizedRamsey'sTheorem:Eachvalueisfinite.
Wehavejustshownthateachofthevaluesfortwocoloringsisafinitenumber.
Let'sshowhowwecanusethisfacttoestablishthateachofthenumbersforthreecoloringsmustalsobefinite.
Consider.
Wewanttoshowthatthereisanumbersothatifwedrawdotsonthepageandcolortheedgeseitherred,blue,orgold,thereissuretobeeitheraredcliqueofdots,orabluecliqueofdots,oragoldcliqueofdots.
Sometimeswhenwesquintoureyes,redandbluecanstarttoeachlookpurple.
Soadiagramwithedgespaintedwiththreecolors,red,blue,andgold,canlooklikeadiagramwithedgespaintedjusttwocolors,purpleandgold,undersquintyeyes.
Thisgivesawaytobringthree-coloringsbacktotwo-colorings.
Let.
(Soanydiagramofdotswithedgespaintedredandbluehaseitheraredcliqueofdotsorabluecliqueofdots.
)Let.
(Soanydiagramofdotswithedgespaintedpurpleorgoldhaseitherapurplecliqueofdotsoragoldcliqueofdots.
)Nowdrawdotsonthepageandcolortheedgesred,blue,andgold.
(Remember,wearelookingforeitheraredcliqueofdotsorabluecliqueofdotsoragoldcliqueofdots.
)Squintyoureyesandseeonlypurpleandgold.
Byourchoiceofwe'reeitherseeingapurplecliqueofdotsoragoldcliqueofdots.
Ifwe'reinthelattercase,thenwe'vefoundoneofthethreethingswewerehopingtosee.
Ifwe'reintheformercase,thenweareseeingapurplecliqueofdots,which,whenweunsquintoureyes,isasetofdotswithredandblueedgesbetweenthem.
Butourchoiceofwasspecial:itguaranteesthateitherwehavearedcliqueofdotsorabluecliqueofdots.
Soagain,weareseeingoneofthethreethingswewerehopingtosee.
Soisfiniteanumber:itisboundedbythenumberwith.
Ingeneral,onereasonsthiswaytoshowthatwith.
Nowknowingthatallthethree-colorRamseyvaluesarefinite,weJamesTanton2016www.
jamestanton.
comandwww.
gdaymath.
comcanusethistoarguethatallthefour-colorRamseynumbersarefinite,whichleadstoallthefive-colorRamseynumbersbeingfinite,andsoon.
CONNECTIONSTOTHEOPENINGPUZZLERHere'saboldclaim:Itisimpossibletocolorthecountingnumberseachoneoffiftypossiblecolorsandavoidamonochromatictriple,,.
(Thegenericcaseisallowed.
)(Thenumber50isimmaterialhere:anyfinitenumberofcolorswilldo!
)Here'swhy.
WejustprovedthattheRamseyvalue,withfiftycolors,isafinitevalue.
Letbeitsvalue.
Soifwedrawdotsonapageandcolortheedgesusingfiftydifferentcolors,thenwearesuretofindamonochromaticcliqueofthree.
Thatis,we'dfindamonochromatictriangle.
Supposewehavecoloredthecountingnumbers1,2,3,…eachoneoffiftycolors.
Drawadotaboveeachofthefirstcountingnumbersanddrawanedgebetweeneachpairdots.
Nowcoloreachedgeaccordingtothefollowingrule:Painttheedgeconnectingthenumbertothenumber(assumehere)withthecolorofnumber.
Amonochromatictriangleissuretoexist.
Fromthistrianglewehavethatthecolorofisthesamethecolorof,whichisthesameasthecolorof.
Butobserve:.
Wehavefoundthreenumbers,,andallthesamecolor.
Exercise:Coloreachpositiveintegeronecolorfromagivenfinitesetofcolors.
Musttherebeamonochromatictriple,,RESEARCHCORNER1.
Letbethesmallestvaluesothatifwecolortheeachofthenumberswithoneofcolorsthereissuretobeamonochromatic"triple".
(Wejustprovedthatexistsand,byeasyextension,thateachvalueexists.
)Wehaveand(ifyoudidthesecondpartoftheopeningexercise).
Canyoudetermineanyothervaluesof2.
Letbethesmallestvaluesothatifwecolortheeachofthenumberswithoneofcolorsthereissuretobeamonochromatictriple.
Wehaveand.
CanyouadjustthepreviousprooftoestablishthatthevaluesexistJamesTanton2016www.
jamestanton.
comandwww.
gdaymath.
com3.
Explorecoloringthepositiveintegerswithafinitepaletteofcolorsandestablishingtheexistenceofamonochromaticquadruple,,,,with.
2016JamesTantontanton.
math@gmail.
com
10gbiz怎么样?10gbiz 美国万兆带宽供应商,主打美国直连大带宽,真实硬防。除美国外还提供线路非常优质的香港、日本等数据中心可供选择,全部机房均支持增加独立硬防。洛杉矶特色线路去程三网直连(电信、联通、移动)回程CN2 GIA优化,全天低延迟。中国大陆访问质量优秀,最多可增加至600G硬防。香港七星级网络,去程回程均为电信CN2 GIA+联通+移动,大陆访问相较其他香港GIA线路平均速度更...
一年一度的黑色星期五和网络星期一活动陆续到来,看到各大服务商都有发布促销活动。同时RAKsmart商家我们也是比较熟悉的,这次是继双十一活动之后的促销活动。在活动产品中基本上沿袭双11的活动策略,比如有提供云服务器七折优惠,站群服务器首月半价、还有新人赠送红包等活动。如果我们有需要RAKsmart商家VPS、云服务器、独立服务器等产品的可以看看他们家的活动。这次活动截止到11月30日。第一、限时限...
raksmart作为一家老牌美国机房总是被很多人问到raksmart香港服务器怎么样、raksmart好不好?其实,这也好理解。香港服务器离大陆最近、理论上是不需要备案的服务器里面速度最快的,被过多关注也就在情理之中了。本着为大家趟雷就是本站的光荣这一理念,拿了一台raksmart的香港独立服务器,简单做个测评,分享下实测的数据,仅供参考!官方网站:https://www.raksmart.com...
魔兽世界服务器维护为你推荐
独立ip空间独立ip主机空间有什么用?企业虚拟主机企业虚拟主机和个人虚拟主机选择有差别吗?租服务器租个服务器?哪里租?中文域名注册查询域名还分中文和英文的吗,在哪里可以查到中文域名到期了?虚拟主机代理虚拟主机代理哪家好,应该选择哪个家?域名购买为什么要购买域名,域名是干嘛用的?域名备案域名备案需要什么香港虚拟空间最稳定香港虚拟主机空间在哪里?手机网站空间谁有上手机网站刷空间人气的网址最好的虚拟主机哪家的虚拟主机比较好?
网易域名邮箱 免费申请网页 zpanel 台湾服务器 阿里云代金券 天猫双十一抢红包 linux空间 空间出租 网站cdn加速 域名接入 东莞主机托管 服务器防火墙 qq金券 lamp兄弟连 杭州电信 phpwind论坛 hosting 服务器是什么意思 服务器操作系统 ssd 更多