bio  website  cwru.edu/artsci/phil/… 

location  Case Western Reserve University  
age  63  
visits  member for  2 years, 9 months 
seen  17 hours ago  
stats  profile views  1,440 
2d

comment 
Example of torsion in orientable manifolds?
@JohnPardon I learned of lens spaces from Seifert and Threlfall when I first began learning of homology and I did not know what mattered about them so I did not retain much. They include $\mathbb{RP}^3$ and a quick introduction is map.mpimbonn.mpg.de/Lens_spaces:_a_history 
2d

comment 
Example of torsion in orientable manifolds?
@QiaochuYuan Yes. I can picture $\mathbb{RP}^3$. But let me check my picture: the torsion 2cycle is the natural projective plane in $\mathbb{RP}^3$, right? 
Jan 28 
accepted  Example of torsion in orientable manifolds? 
Jan 28 
asked  Example of torsion in orientable manifolds? 
Jan 27 
comment 
Who first talked about “holes” in homology?
@paulgarrett I really appreciate this input, but I see that as Alexandroff uses the term "hole," there cannot be any holes in a closed surface (i.e. in a compact boundaryless surface). Homology certainly does not count holes in his sense. 
Jan 27 
revised 
Who first talked about “holes” in homology?
Notice that even Alexandroff does not say that torus, for example, has "holes". 
Jan 27 
revised 
Who first talked about “holes” in homology?
Added discussion of where the term is not used. 
Jan 27 
comment 
Who first talked about “holes” in homology?
@paulgarrett Also, we see what is going on around us. With a 1977 Princeton PhD you might well have heard Atiyah himself use the term. You certainly knew people who did. 
Jan 27 
awarded  Custodian 
Jan 27 
comment 
Who first talked about “holes” in homology?
@paulgarrett Nice call. That is a stunning book. But I think he only uses the term "hole" in passing and does not offer it as a general explanation of the genus of a surface or of homology groups. 
Jan 27 
reviewed  Approve Help in understanding “Local wellposedness for the MaxwellSchrodinger system” 
Jan 27 
comment 
Who first talked about “holes” in homology?
@AlexDegtyarev Then you really should read Atiyah's essay. 
Jan 27 
asked  Who first talked about “holes” in homology? 
Jan 9 
comment 
What is known about global well ordering of classes in GödelBernays?
A beautiful result. I fear it sinks my strategy for the problem that led to this question, but maybe that failure points the way to what will work. 
Jan 9 
accepted  What is known about global well ordering of classes in GödelBernays? 
Jan 7 
comment 
What is known about global well ordering of classes in GödelBernays?
Terrific. I will take some time to absorb this. Since I really want this in a weak fragment of ZFC, the use of $Z_2$ is very encouraging. 
Jan 7 
comment 
What is known about global well ordering of classes in GödelBernays?
@AsafKaragila I want well ordering not in classes, but of classes. 
Jan 7 
asked  What is known about global well ordering of classes in GödelBernays? 
Dec 27 
accepted  What is the consistency strength of a standard model of ZF versus a transitive model? 
Dec 27 
comment 
What is the consistency strength of a standard model of ZF versus a transitive model?
@AndresCaicedo Compared to proof theory, I tend to think of set theory as having all settled terminology. I have clarified in the question. 