%   ORIGINAL: 'h4/thm/pred_set/UNION_ASSOC_'
% Assm: HL_TRUTH: T
% Assm: HL_FALSITY: ~F
% Assm: HL_BOOL_CASES: !t. (t <=> T) \/ (t <=> F)
% Assm: HL_EXT: !f g. (!x. f x = g x) ==> f = g
% Goal: !s t u. 'h4/const/pred_set/UNION' s ('h4/const/pred_set/UNION' t u) = 'h4/const/pred_set/UNION' ('h4/const/pred_set/UNION' s t) u
%   PROCESSED
% Assm ['HL_TRUTH']: T
% Assm ['HL_FALSITY']: ~F
% Assm ['HL_BOOL_CASES']: !t. (t <=> T) \/ (t <=> F)
% Assm ['HL_EXT']: !f g. (!x. happ f x = happ g x) ==> f = g
% Goal: !s t u. 'h4/const/pred_set/UNION' s ('h4/const/pred_set/UNION' t u) = 'h4/const/pred_set/UNION' ('h4/const/pred_set/UNION' s t) u
fof('HL_TRUTH', axiom, p(s(bool,'T'))).
fof('HL_FALSITY', axiom, ~ (p(s(bool,'F')))).
fof('HL_BOOL_CASES', axiom, ![T]: (s(bool,T) = s(bool,'T') | s(bool,T) = s(bool,'F'))).
fof('HL_EXT', axiom, ![V_3f15344,V_3f15340]: ![F, G]: (![X]: s(V_3f15340,happ(s(fun(V_3f15344,V_3f15340),F),s(V_3f15344,X))) = s(V_3f15340,happ(s(fun(V_3f15344,V_3f15340),G),s(V_3f15344,X))) => s(fun(V_3f15344,V_3f15340),F) = s(fun(V_3f15344,V_3f15340),G))).
fof('h4/thm/pred_set/UNION_ASSOC_', conjecture, ![A]: ![S, T, U]: s(fun(A,bool),'h4/const/pred_set/UNION'(s(fun(A,bool),S),s(fun(A,bool),'h4/const/pred_set/UNION'(s(fun(A,bool),T),s(fun(A,bool),U))))) = s(fun(A,bool),'h4/const/pred_set/UNION'(s(fun(A,bool),'h4/const/pred_set/UNION'(s(fun(A,bool),S),s(fun(A,bool),T))),s(fun(A,bool),U)))).
