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bio website wildcatsformma.wordpress.com
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visits member for 2 years, 7 months
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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

My Website:WildCats
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My non-scientific interests:

  • Skiing, Sailing, Windsurfing
  • Argentine Tango dancer

More or less fluent in (random order):

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


Jun
5
comment Uniqueness of the Comparison Functor
@Chilango you are welcome, my pleasure :-)
Jun
4
answered Uniqueness of the Comparison Functor
Jun
4
comment Uniqueness of the Comparison Functor
what does it mean $U\in D$ ? $U$ is a functor and $D$ is a category
Jun
4
comment Types, Sets and Categories
@CristianGarcia I am glad :-)
Jun
3
answered Types, Sets and Categories
May
30
revised Is there a concept of a “free Hilbert space on a set”?
edited typo in formula
May
30
suggested suggested edit on Is there a concept of a “free Hilbert space on a set”?
May
25
comment Exercise from Rotman, direct limit of quotient modules
@WLOG Thank you :-)
May
25
comment Exercise from Rotman, direct limit of quotient modules
@WLOG Could you please write where is this exercise in Rotman?
May
25
revised morphisms in $Vect_k^\otimes$
edited tex in title
May
25
suggested suggested edit on morphisms in $Vect_k^\otimes$
May
24
comment Showing that a diagram commutes in the most economical way
@R.N. It is a generalization of the situation depicted by Pece in his comment above
May
23
comment Showing that a diagram commutes in the most economical way
@R.N. I added an optimization procedure, perhaps this is what you were looking for
May
23
revised Showing that a diagram commutes in the most economical way
added optimization
May
23
comment Showing that a diagram commutes in the most economical way
@LeenDroogendijk What is a "directed $P_5$...." ? In any case, you (might) have a special category, but the question is very clear, in the last paragraph it says:"In general, given a diagram....", so your (or any other) special example is not relevant to the OP.
May
23
answered Showing that a diagram commutes in the most economical way
May
14
comment For which values of $a$ is this set a manifold?
No Cure , Jeremy's answer is correct. I was referring to what you wrote in your question.
May
12
comment Diffeomorphic connected hypersurfaces
To give $A^\mu$ a chance to exist, it should be on the plane spanned by $n'$ and $n$
May
12
comment Diffeomorphic connected hypersurfaces
In that case the answer is no, there is no such $A^\mu$ lying at the intersection of the 2 hypersurfaces: take 1+2 flat spacetime with 2 inertial frames (primed and unprimed) moving along the common x axis. Then the intersection is the common y axis. Now $e_{t'} = a e_t + b e_x$ (it has a x component). Vector $A = \alpha (x,y,t) e_y$. $\mathcal{L}_A e_t$ does not have a x component and neither do its $\mathcal{L}_A$ iterates. So $\exp(\mathcal{L}_A)e_t$ does not have a x component and we cannot get $e_{t'}$
May
12
comment Diffeomorphic connected hypersurfaces
If there were such a vector field, how would you relate it to the (certainly existing) diffeomorphism between the 2 foliations?