let T be reflexive transitive antisymmetric with_suprema adj-structured TA-structure ; :: thesis: for A being Subset of the adjectives of T
for t being type of T st A is_applicable_to t holds
(types A) /\ (downarrow t) is Ideal of T

let A be Subset of the adjectives of T; :: thesis: for t being type of T st A is_applicable_to t holds
(types A) /\ (downarrow t) is Ideal of T

let t be type of T; :: thesis: ( A is_applicable_to t implies (types A) /\ (downarrow t) is Ideal of T )
given t9 being type of T such that A1: A c= adjs t9 and
A2: t9 <= t ; :: according to ABCMIZ_0:def 16 :: thesis: (types A) /\ (downarrow t) is Ideal of T
A3: t9 in downarrow t by A2, WAYBEL_0:17;
t9 in types A by A1, Th14;
hence (types A) /\ (downarrow t) is Ideal of T by A3, WAYBEL_0:27, WAYBEL_0:44, XBOOLE_0:def 4; :: thesis: verum