・Slightly modified the initial portion of the discussion of Example 3.6 in the Introduction
・Slightly modified the wording in the Introduction ("higher and higher levels" ---> "new levels")
・Added some references to [IUTchIII] to the discussion of vertical and horizontal cores in the Introduction
・Updated the Acknowledgements
・Corrected a misprint ("stament" ---> "statement") in the second paragraph of the proof of Proposition 1.4
・Corrected a misprint ("is does" ---> "does") in the observation "(R3)" in Step (iii) of the proof of Theorem 1.10
・Slightly modified the phrasing of the display immediately following the discussion of the notion of a ZFCG-model
・Slightly modified the reference to [Drk] in Remark 3.1.1
・Slightly modified the final sentence of Remark 3.1.2, (i)
・Corrected a misprint ("Definition 3.2" ---> "Definition 3.3") in Remark 3.1.5
・Slightly modified the final sentence of Definition 3.3, (iii)
・Slightly modified the final sentence of Remark 3.3.1, (i)
・Slightly modified the final two sentences of Remark 3.3.1, (ii); deleted the Bibliographical entries for [LgSch], [ArLgSch];
added a Bibliographical entry for [MnLg]
・Slightly modified the first sentence of Example 3.5, (iv)
・Rewrote Example 3.6, (i)
・Corrected misprints in the final display of Example 3.6, (iii), and the following discussion
・At the end of Remark 3.6.1, (ii), replaced "3.12.3" by "3.12.2"
・In Remark 3.6.2, (i), added a reference to Remark 3.1.5
・Slightly modified the wording ("to the set" ---> "to the power set") in Remark 3.6.2, (iii)
・In Remark 3.6.3, (i), added a supplementary explanatory phrase concerning the notation