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bio website wildcatsformma.wordpress.com
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My scientific interests:

  • Mathematics: Category Theory, Algebra, Logic (Model-Theory, ATP), Control Systems
  • Physics: General Relativity, QFT
  • Amateur Astronomer and Astrophotographer
  • Mathematica programming

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My non-scientific interests:

  • Skiing, Sailing, Windsurfing
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More or less fluent in (random order):

Italian, English, German, French, Spanish, Dutch and struggling with Russian


Jul
6
revised When equal products imply equal factors?
multipliers -> factors
Jul
6
comment When equal products imply equal factors?
@Hurkyl is the one getting closer to the heart of the question.
Jul
6
suggested suggested edit on When equal products imply equal factors?
Jul
6
revised When equal products imply equal factors?
multipliers -> factors in the title
Jul
6
suggested suggested edit on When equal products imply equal factors?
Jul
6
comment A question regarding the definition of natural transformation
what do you mean by "just imagine them" ? in any case, as @andy explained below, the answer is YES, they are always morphisms of the target category D
Jul
6
comment What does Simmons mean by “closure” in this exercise?
what is the relationship between the A,B in the text and the S,T in the formulas?
Jul
6
comment Meaning of commutative diagram
@ŁukaszMaciejewski I do not see much resemblance with any commutative axiom. The name commutative refers to the fact that you can commute (ie. exchange) two paths with the same starting and ending points, and you get the same result
Jul
3
revised For which categories we can solve $\text{Aut}(X) \cong G$ for every group $G$?
Added "group" to title
Jul
3
suggested suggested edit on For which categories we can solve $\text{Aut}(X) \cong G$ for every group $G$?
Jun
28
comment Does 'much' of what is known about groups carry over to groupoids?
Perhaps it would be best to decide for yourself Alan, and then report it here. I recently found some good groupoid books by Ronald Brown on the net. Go to Wikipedia on groupoids and look at the references there.
Jun
15
answered Intuition for Coconstant morphisms
Jun
11
answered Properties of functors
Jun
10
comment Natural transformation
There seems to be something strange in your formulas. In the first equation you have: $$(g,h)\stackrel{F_H(\alpha)}{\mapsto} (\alpha(g),h)$$ So $F_H(\alpha)$ does not seem to change the second component of its argument ($(g,h)$ in this case), while in your second formula: $$(g,f(g))\stackrel{F_K(\alpha)}{\mapsto}(\alpha(g),f(h))$$ $F_K(\alpha)$ seems to also act on the second component of its argument ($(g,f(g)$ in this case). So your notation is not consistent, or if you prefer natural in H or K. And it should be, I think.
Jun
10
revised Natural transformation
changed xGrp to Grp in second paragraph equation
Jun
10
comment Natural transformation
@QiaochuYuan +1 for "interval category". Is it a somewhat standard name (in topology maybe) ? MacLane calls it simply "$\mathbf{2}$"
Jun
10
suggested suggested edit on Natural transformation
Jun
8
awarded  Constituent
Jun
8
awarded  Caucus
Jun
3
comment Existence of non-identity natural transformations $\tau:F \to F $
@ZhenLin just a notational curiosity: why did you write BG ? what does the double strike B stand for? Is it standard notation?