set D = AltCatStr(# the carrier of C, the Arrows of C, the Comp of C #);
reconsider D = AltCatStr(# the carrier of C, the Arrows of C, the Comp of C #) as SubCatStr of C by Def11;
take D ; :: thesis: ( D is full & D is strict )
thus the Arrows of D = the Arrows of C || the carrier of D ; :: according to ALTCAT_2:def 13 :: thesis: D is strict
thus D is strict ; :: thesis: verum