Peter LeFanu Lumsdaine

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3,480 reputation
1231
bio website mathstat.dal.ca/…
location Stockholm, Sweden
age 31
visits member for 4 years, 9 months
seen 23 hours ago

math.LO/math.CT, currently postdoc at Stockholm University. Previously Institute for Advanced Study, Princeton, lately of Dalhousie University, Nova Scotia, and Carnegie Mellon University, Pittsburgh.


Sep
16
revised discrete-morse-theory wiki description
initiated wiki entry for new tag
Sep
16
revised discrete-morse-theory wiki excerpt
initiated wiki entry for new tag
Sep
16
revised Morse matching with 0-cells and (n-1)-cells
retagged (now that this tag exists)
Sep
16
revised Discrete Morse theory and chess
retagged (now that tag exists)
Sep
16
suggested suggested edit on discrete-morse-theory tag wiki
Sep
16
wiki created discrete-morse-theory description
Sep
16
wiki created discrete-morse-theory excerpt
Sep
16
suggested suggested edit on discrete-morse-theory tag wiki excerpt
Sep
16
revised Using Discrete Morse Theory to represent hom classes
edited tags
Sep
15
comment Results true in a dimension and false for higher dimensions
To elaborate on this: in dimensions ≥3 there are finite paradoxical decompositions of the unit ball; in dimensions 1 and 2, paradoxical decompositions must be countably infinite; and in dimension 0, there are none.
Sep
15
revised Besides the tracioid are there other surfaces of revolution that have a constant negative curvature?
made answer a little more informative without needing to click through
Sep
7
revised Pseudonyms of famous mathematicians
updated link, as per comments (while this thread is already recently bumped)
Jul
29
comment Do direct limits (filtered colimits) commute with pullbacks, in C*-algebras?
Both at math.se and here, the title was rather unclear, which I think is why there’s been some misunderstanding and negative reactions in comments (including thinking that the question was more trivial than it is). I’ve edited the title to give the actual question a bit more clearly; hopefully I’ve understood OP’s intentions correctly.
Jul
29
revised Do direct limits (filtered colimits) commute with pullbacks, in C*-algebras?
Clarified title to give question more specifically
Jul
25
comment Why do Lie algebras pop up, from a categorical point of view?
“The category of Lie algebras is equivalent to a certain category of cocommutative Hopf algebras” — do you know a good reference that works this out or states it more precisely? Or at least some specific term which readers can google for more details?
Jul
21
comment Rediscovery of lost mathematics
@hobbs: it reminds me nicely of Lewis Carroll’s long but charming Phantasmagoria, which also uses a mixed pattern of 4-foot and 3-foot lines, in that case in 5-line stanzas (4 / 3 / 4 / 4 / 3).
Jul
2
awarded  Curious
May
9
comment Does Grothendieck have any pseudonymous paper?
@quid: it is certainly sensationalist, but in what way is it vague? The criterion for answers seems quite clear: publicly available work that does not carry Grothendieck's name, but which there's some reason to believe that Grothendieck may have written.
May
2
comment Submitting a companion paper with detailed proofs ?
@TimothyChow: while I don't disagree with your points in general, the length restriction in JAMS seems to be no longer current --- looking at recent issues, most have at least one paper of $\geq$ 60pp, and there are even a few around the hundred-page mark.
Apr
29
answered Generalizing indexed coproduct from $\mathrm{Set}$ to other monoidal categories