Kang, Cho, and Ko gave a structure theorem for some classes of perfect ideals of grade 3 which are linked to almost complete intersections by a regular sequence. We define a 5 x 9 matrix f determined by three matrices A, T, and Y and construct a class of perfect ideals K-4(f) of grade 3 defined by f . This contains a class of perfect ideals of grade 3 minimally generated by five elements which are not Gorenstein. We give a structure theorem for some classes of perfect ideals of grade 3 linked to K-4(f) by a regular sequence in K-4(f).
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