A typical first-order jump looks like

(...
 (const p (code somewhere ...))
 (jump p a1 a2))

Cogen needs to know the destination of the jump in order to generate an extension for it (see jumps). Thus the code-pointer must be in the binding time. The lattice can be extended to include constants (though only constants that are code-pointers are needed for jumps, other constants come in handy):

bt ::= S | D | (cons bt bt cp) | (const v)
cp ::= instruction
v ::= any-value

BTs that are constants are called metastatic because when a specializer is self-applied they are static for the outer specializer (the one that is analyzing the inner specializer).

Formal ordering requires an additional rule:

(const v) < S

Since metastatic values are incomparable, this doesn't introduce any infinite ascending chains.