לשנה טובה תיכתבו ותיחתמו

New improved organic honey and apples this Hakhel year!

Armenian Journal of Mathematics

A note on omitting types in propositional logic has appeared here: http://www.flib.sci.am/eng/journal/Math/

Mathoverflow: http://mathoverflow.net/

Mathoverflow is full of interesting discussions; I try to follow those in set theory and logic under the pseudonym avshalom.

http://mathoverflow.net/

New item in mathematical logic: M-slenderness; (with Burkhard Wald).

לשנה טובה תיכתבו ותיחתמו

Apples and honey! What could be better?

Can Aronszajn lines or Suslin lines ever be the orderings of abelian groups?

A torsion-free abelian group A is orderable, i.e. there is a linear order < on A such that if g < h then g + k < h + k for all g, h, k in A. The question is whether Suslin lines or Aronszajn lines can ever be orderings of abelian groups. See http://mathoverflow.net/questions/179618/can-suslin-lines-ever-be-orderings-of-abelian-groups

Robert Solow on the Piketty proposal

I wonder whether Piketty's proposal might replace one wealth-correlated inequality by an equally frightening one that would arise through the quasi-mechanical ademocratic devolution of power to a global revenue collector (read state) enabling the increased taxation of capital and its transmission. Are the statistical grounds for the conclusion of his analysis really that strong? Inequality and inequity are neither synonymous nor coextensive. The worst inequity (probably) occurs in the quantiles of the poorest most vulnerable members of society. One needs statistics to capture the skewed distribution and to adjust the measures accordingly. Is one attempting to move the mean to the right or to reduce the variance or other higher order moments? A linear shift in the mean will not change the shape of the curve describing the distribution of wealth. Trusting a global state to redistribute is as sensible as preaching the virtues of vegetarianism to a hungry fox in a well-stocked hen house.
Robert Solow's review is as lucid as ever (even if I dare to diverge): http://www.newrepublic.com/article/117429/capital-twenty-first-century-thomas-piketty-reviewed.