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visits member for 4 years, 10 months
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Dec
17
answered A More Advanced Version of Aluffi's Chapter 0
Dec
16
comment Differential Algebra Book
Aren't F4 and F5 purely for polynomial rings? Or do they have differential analogues?
Dec
10
answered Differential Algebra Book
Nov
22
reviewed Approve Solutions for n such that the path number to the n-th node is also n in a complete, rooted, ordered k-ary tree
Nov
3
comment Any reason I should join ResearchGate?
Do you like getting lots of useless email you will never read? Then ResearchGate is for you.
Jul
2
awarded  Curious
May
3
comment Does GL_n(Z) have a noetherian group ring?
I believe the only known examples of groups with Noetherian group rings are polycyclic-by-finite groups.
Apr
24
reviewed Approve Fixed point of a function on the circle
Apr
22
reviewed Reject nontrivial theorems with trivial proofs
Apr
12
comment Is there a name for functions f(x,y) that are only convex in x (and continuous in y).
I personally would write "convex in x".
Mar
31
reviewed Approve On a modal correspondence
Mar
23
comment On the foundations for large categories
I'm skeptical that there is any agreement on this ZFC + 3 universes business. As far as I can see, most theorems in a standard introductory category theory book can be formulated in ZFC alone. (There are a few results whose proofs require the existence of the skeleton of an arbitrary category, which doesn't hold in ZFC, but holds in a conservative extension.)
Mar
23
comment On the foundations for large categories
Anyway, the axiom of universes is a large cardinal axiom, just a small large cardinal axiom.
Mar
23
comment On the foundations for large categories
@ZhenLin: I don't understand your statements about first-order logic. You can quantify over classes, in Goedel-Bernays or Kelley-Morse set theory. If you really want to, you can write a first-order formulation that allows collections of classes (this is the formulation that "Abstract and Concrete Categories" has in mind, though the book doesn't write it out explicitly).
Mar
20
reviewed Approve Fractional Derivative of A specific function
Mar
20
reviewed Approve Fractional Derivatives Of Sums
Mar
20
reviewed Approve Finding the Fractional Derivative of This Function
Mar
16
reviewed Approve The number of connected components of a generalized hypecube
Mar
16
reviewed Approve When does direct image with proper support have a right adjoint?
Mar
11
revised separated schemes
fix latex