| http://www.w3.org/ns/prov#value | - wherein n is a number of at least 2, i is a positive integer not larger than n, Y is an aromatic or substituted aromatic group, and X is O, S, Se, Te or the divalent group --CH???CH--, and a tetracarboxylic dianhydride of the formula: ##STR5## wherein A is a tetravalent hydrocarbon group in a molar ratio of the diamine to the dianhydride of 1: (1+m) wherein m is a positive number, preferably less
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