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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 suggested edit on 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 suggested edit on Fractional Derivative of A specific function
Mar
20
reviewed Approve suggested edit on Fractional Derivatives Of Sums
Mar
20
reviewed Approve suggested edit on Finding the Fractional Derivative of This Function
Mar
16
reviewed Approve suggested edit on The number of connected components of a generalized hypecube
Mar
16
reviewed Approve suggested edit on When does direct image with proper support have a right adjoint?
Mar
11
revised separated schemes
fix latex
Mar
11
reviewed Approve suggested edit on Color identical pairs and the 4-color theorem
Mar
9
awarded  Custodian
Mar
9
reviewed No Action Needed Lie Group Isomorphisms
Mar
7
awarded  Good Answer
Mar
6
revised Does the going-up theorem hold between flat algebras?
minor latex and grammar fixes
Mar
6
awarded  Nice Answer
Mar
6
answered Who made the famous error in calculation that 'wasted' the final years of his life?
Mar
4
reviewed Reject suggested edit on How is the Fractal Dimension of a Parametric Curve Related to the Fractal Dimensions of its Coordinate Functions?
Mar
3
reviewed Approve suggested edit on Is the universal enveloping algebra of the free Poisson algebra generated by finite set (left)-noetherian?