[FOM] Primitive and defined symbols for mereology

[Neil Tennant]

Could anyone on the fom list please do me the kind favo(u)r of listing the
preferred symbols in use among mereologists nowadays? It would be 
especially helpful if their LaTeX codes could be supplied.

Let me illustrate what I am after by using the easier case of set theory:

$x\in y$	 x is a member of y		
$\{x\mid Fx\}$   the set of all Fs
$x\cup y$	 the union of x and y
$\bigcup x$	 the union of x
$x\subseteq y$	 x is a subset of y	 
$x\subset y$	 x is a proper subset of y

I am especially concerned to know how the operation of fusion is formally
represented. With two individuals x and y, the fusion of x and y would
seem to be representable by a two-place function-term such as f(x,y).
But what is the convention when the fusion is taken of all the individuals
in some infinite set? Does mereology have a way of representing this
operation without recourse to set-theoretic notions? Or does it resort to
the hybrid notion of the fusion of all the individuals in such-and-such a
set or family?

What is the best canonical source for a formal axiomatization of 
mereology?

Finally, what are the most important open foundational problems in
mereology?

Neil Tennant