(2018-10-02)

・Corrected a misprint (an intended subscript that was not subscripted) in
　the first object appearing in the composite of "isomorphisms" in (HolMod)

(2018-11-08)

・Slightly modified the discussion at the end of \S 3

・Added (UnEx3)

・Rewrote (LVEx)

(2018-11-26)

・Added (RLFU) and modified (VUC1) accordingly

(2018-12-28)

・Slightly modified the wording of (LbEx4) and added (LbEx6)

(2019-02-01)

・Slightly modified (AD)

・Modified (LbEx6)

・Corrected a misprint in (DfLb) ("appartuses" ---> "apparatuses")

・Slightly modified (MlCr2)