Cascading nil nodes in Metapattern

Pieter Wisse, Information Dynamics

Metapattern’s formalization in both Multicontextual paradigm for object orientation: a development of information modeling toward fifth behavioral form (Information Dynamics, translated from original Dutch version, 1991-1994; English version also published in: Informatiekundige ontwerpleer, Ten Hagen Stam, 1999) and Metapattern: context and time in information models (Addison-Wesley, 2001; relevant extract from part I published as The pattern of metapattern: ontological formalization of context and time for open interconnection, in: PrimaVera, working paper 2004-01, Amsterdam University, 2004.) includes that some partial identity of one object (y) may serve as another object’s (x) nil identity. In Metapattern (p. xxvii), it is shown that "chains of derivational relationships" may be built. With k for node, applying the symbolic language used in Metapattern, that is:

k_x,0 = k_y,n.

The boundary for cascading nil nodes is of course established by the so-called nil object with its corresponding (nil) identity, aka horizon. Please note that the resulting cascade need not be strictly oriented at the horizon all of its way; it may, say, meander toward it.

In actual modeling practice, “chains of derivational relationships” through cascading nil nodes are a prominent feature of Metapattern. See modeling exercises with Metapattern for a compilation.

Making cascading nil nodes easier to draw, and thereby information models overall clearer to read et cetera, has been the primary motivation for partially changing, about 2002, Metapattern’s notation; see Metapattern, development of notation.