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
RAKsmart发布了9月份优惠促销活动,从9月1日~9月30日期间,爆款美国服务器每日限量抢购最低$30.62-$46/月起,洛杉矶/圣何塞/香港/日本站群大量补货特价销售,美国1-10Gbps大带宽不限流量服务器低价热卖等。RAKsmart是一家华人运营的国外主机商,提供的产品包括独立服务器租用和VPS等,可选数据中心包括美国加州圣何塞、洛杉矶、中国香港、韩国、日本、荷兰等国家和地区数据中心(...
Hostodo近日发布了美国独立日优惠促销活动,主要推送了四款特价优惠便宜的VPS云服务器产品,基于KVM虚拟架构,NVMe阵列,1Gbps带宽,默认分配一个IPv4+/64 IPv6,采用solusvm管理,赠送收费版DirectAdmin授权,服务有效期内均有效,大致约为7折优惠,独立日活动时间不定,活动机型售罄为止,有需要的朋友可以尝试一下。Hostodo怎么样?Hostodo服务器好不好?...
vollcloud LLC创立于2020年,是一家以互联网基础业务服务为主的 技术型企业,运营全球数据中心业务。致力于全球服务器租用、托管及云计算、DDOS安 全防护、数据实时存储、 高防服务器加速、域名、智能高防服务器、网络安全服务解决方案等领域的智 能化、规范化的体验服务。所有购买年付产品免费更换香港原生IP(支持解锁奈飞),商家承诺,支持3天内无条件退款(原路退回)!点击进入:vollclo...
魔兽世界服务器维护为你推荐
域名注册网站有没有免费的域名注册?.net虚拟主机虚拟主机如何设置net版本?虚拟主机购买虚拟主机需要购买吗?我想自己做个网站,只买了域名了,请问还需要怎么做呢?国外空间租用租用美国空间中文域名注册查询哪里有可以查询中文域名是否被注册的地方?台湾主机台湾的电脑硬件比韩国,日本,美国强?深圳网站空间求免费稳定空间网站?重庆网站空间重庆有没有发展空间?100m虚拟主机100M的虚拟主机都能做些什么长沙虚拟主机长沙IDC,求长沙本地虚拟主机,大伙推荐推荐
青岛虚拟主机 主机域名 美国域名注册 双线服务器租用 vps优惠码cnyvps 代理域名备案 kvmla gomezpeer 密码泄露 免费静态空间 主机合租 php空间申请 河南m值兑换 789电视网 佛山高防服务器 免费智能解析 微软服务器操作系统 电信托管 中国电信宽带测速器 宏讯 更多