I'm trying to track down the origin of the geometry collection concept. Did it originate inside or outside GIS? JSTOR has nothing for me. Via Martin Davis, I've found a paper by Egenhofer and Herring  [PDF] which mentions a "complex line" on page 6:
– A complex line is a line with more than two disconnected boundaries (Figure 1d).
but makes no mention of multipoints, multilines, or multipolygons. Figure 1d in that paper shows a forking line, like a lower-case Greek lamba: λ.
Anybody have a good reference?