Andthey'llsay, Well, a Kleinbottledoesn't reallyhaveanyvolume.
It's a topelogicalshape.
Thisdoesn't havevalue, butwait a second.
Lookslikeithasvolume.
Well, ifyouaskapologisedDoes a measuringcuphavevolume?
They'llprobablytellyouno.
Does a spherehavevolume?
Yep.
Nomatterhowhot.
Youknow, youknow, fourpi r cubedwhatever.
Ithas a volume.
Itdividestheuniverseintoanoutsideanditinside.
Andnomatterhowyoustretchandcontortitinthe A, shrinkitifyoumakeitbigger, it'llalwayshave a volume.
Oh, a pieceofpaper.
I canmakeitintosortof a cupsomehoworanother, but I'llalwaysoccupiedverylittlevaluable, youknow, inthelimit.
None.
Likewise.
A bagright.
I canputstuffinandputstuffintoit.
I evenputstuffthathasvolumeintoit.
Butitdoesn't dividetheuniverse.
Itdoesn't dividetheuniverseintotwoparts.
If I wereinouterspace.
Allofthesegrapewouldfloatout a bagdoesn't divideouruniverseintotwoparts.
Thisisrelatedcloselyto a twodimensionalproblemcalledtheJordanCurveProblems, whichasks a coolquestionofIsthere a differencebetweenthatcurveandthisothercurvethisenclosesinareaThisdoesn't encloseanareaturnsouttobe a surprisinglydifficultthingtoprove.