[TYPES] Formal treatment of intersection/union/arrow subtyping?

[Steffen van Bakel]

Hi Dan,

This is to inform you that I have just updated my paper,

	Subject Reduction vs Intersection / Union Types for lambda-bar-mu-mu- 
tilde

available at http://www.doc.ic.ac.uk/~svb/Research.  The previous  
version was not complete.

That said, Mariangiola's statement still holds: subject reduction  
collapses also in a 'simple' system, where the only subtype relation  
is the one induced by commutativity and associativity of both union  
and intersection.  Also, it is not just union that creates a problem.

Best,

Steffen van Bakel
Imperial College London