Script(s) to generate "umbrella" definitions for period concepts, or definitions made of definitions, by aggregating the date ranges of period definitions across collections that share the same label and geographic coverage (e.g. all the examples of the "Archaic" period in Greece).
make init
periodo-umbrellas create http://n2t.net/ark:/99152/p08m57h7d5h http://n2t.net/ark:/99152/p08m57hdsg5