|  | Who Cites st  app? | 
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| st_app | Def st_app(c1;c2) == (  s2  c2.(  s1  c1.st_app1(s1;s2))) | 
 | |  | Thm*  c1,c2:Collection(SimpleType). st_app(c1;c2)  Collection(SimpleType) | 
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| st_app1 | Def st_app1(s1;s2) == Case(s1) Case a;b = >  if st_eq(a;s2)  < b >  else  <  >  fi Default = >   <  > | 
 | |  | Thm*  s1,s2:SimpleType. st_app1(s1;s2)  Collection(SimpleType) | 
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| st | Def SimpleType == Tree(Label+Unit) | 
 | |  | Thm* SimpleType  Type | 
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| col_accum | Def (  x  c.f(x))(y) ==  x:T. x  c  &  y  f(x) | 
 | |  | Thm*  T,T':Type, f:(T   Collection(T')), c:Collection(T). (  x  c.f(x))  Collection(T') | 
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| col_none | Def  <  > (x) == False | 
 | |  | Thm*  T:Type.  <  >  Collection(T) | 
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| st_eq | Def st_eq(s1;s2) == Case(s1) Case a;b = >  Case(s2) Case a';b' = >  st_eq(a;a')   st_eq(b;b') Default = >  false  Case tree_leaf(x) = >  Case(s2) Case a';b' = >  false  Case tree_leaf(y) = >  InjCase(x; x'. InjCase(y; y'. x' =  y'; b. false  ); a. InjCase(y; y'. false  ; b. true  )) Default = >  false  Default = >  false  (recursive) | 
 | |  | Thm*  s1,s2:SimpleType. st_eq(s1;s2)    | 
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| lbl | Def Label == {p:Pattern|  ground_ptn(p) } | 
 | |  | Thm* Label  Type | 
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| eq_lbl | Def l1 =  l2 == Case(l1) Case ptn_atom(x) = >  Case(l2) Case ptn_atom(y) = >  x=  y  Atom Default = >  false  Case ptn_int(x) = >  Case(l2) Case ptn_int(y) = >  x=  y Default = >  false  Case ptn_var(x) = >  Case(l2) Case ptn_var(y) = >  x=  y  Atom Default = >  false  Case ptn_pr( < x, y > ) = >  Case(l2) Case ptn_pr( < u, v > ) = >  x =  u   y =  v Default = >  false  Default = >  false  (recursive) | 
 | |  | Thm*  l1,l2:Pattern. l1 =  l2    | 
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| ground_ptn | Def ground_ptn(p) == Case(p) Case ptn_var(v) = >  false  Case ptn_pr( < x, y > ) = >  ground_ptn(x)   ground_ptn(y) Default = >  true  (recursive) | 
 | |  | Thm*  p:Pattern. ground_ptn(p)    | 
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| case_default | Def Default = >  body(value,value) == body | 
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| col_singleton | Def  < x > (y) == y = x  T | 
 | |  | Thm*  T:Type, x:T.  < x >  Collection(T) | 
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| case_node | Def Case x;y = >  body(x;y) cont(x1,z) == InjCase(x1; _. cont(z,z); x2. x2/x3,x2@0. body(x3;x2@0)) | 
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| case | Def Case(value) body == body(value,value) | 
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| tree | Def Tree(E) == rec(T.tree_con(E;T)) | 
 | |  | Thm*  E:Type. Tree(E)  Type | 
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| col_member | Def x  c == c(x) | 
 | |  | Thm*  T:Type, x:T, c:Collection(T). x  c  Prop | 
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| case_tree_leaf | Def Case tree_leaf(x) = >  body(x) cont(x1,z) == InjCase(x1; x2. body(x2); _. cont(z,z)) | 
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| band | Def p   q == if p  q else false  fi | 
 | |  | Thm*  p,q:  . (p   q)    | 
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| assert | Def  b == if b  True else False fi | 
 | |  | Thm*  b:  . b  Prop | 
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| ptn | Def Pattern == rec(T.ptn_con(T)) | 
 | |  | Thm* Pattern  Type | 
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| tree_con | Def tree_con(E;T) == E+(T  T) | 
 | |  | Thm*  E,T:Type. tree_con(E;T)  Type | 
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| case_lbl_pair | Def Case ptn_pr( < x, y > ) = >  body(x;y) cont(x1,z) == InjCase(x1; _. cont(z,z); x2. InjCase(x2; _. cont(z,z); x2@0. InjCase(x2@0; _. cont(z,z); x2@1. x2@1/x3,x2@2. body(x3;x2@2)))) | 
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| eq_atom | Def x=  y  Atom == if x=y  Atom  true  ; false  fi | 
 | |  | Thm*  x,y:Atom. x=  y  Atom    | 
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| case_ptn_var | Def Case ptn_var(x) = >  body(x) cont(x1,z) == (  x1.inr(x2) = >  (  x1.inr(x2) = >  (  x1.inl(x2) = >  body(hd([x2 / tl(x1)])) cont(hd(x1),z))([x2 / tl(x1)]) cont(hd(x1),z))([x2 / tl(x1)]) cont(hd(x1),z))([x1]) | 
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| eq_int | Def i=  j == if i=j  true  ; false  fi | 
 | |  | Thm*  i,j:  . (i=  j)    | 
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| case_ptn_int | Def Case ptn_int(x) = >  body(x) cont(x1,z) == (  x1.inr(x2) = >  (  x1.inl(x2) = >  body(hd([x2 / tl(x1)])) cont(hd(x1),z))([x2 / tl(x1)]) cont(hd(x1),z))([x1]) | 
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| case_ptn_atom | Def Case ptn_atom(x) = >  body(x) cont(x1,z) == InjCase(x1; x2. body(x2); _. cont(z,z)) | 
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| ptn_con | Def ptn_con(T) == Atom+  +Atom+(T  T) | 
 | |  | Thm*  T:Type. ptn_con(T)  Type | 
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| hd | Def hd(l) == Case of l; nil  "?" ; h.t  h | 
 | |  | Thm*  A:Type, l:A List. ||l||  1   hd(l)  A | 
 | |  | Thm*  A:Type, l:A List  . hd(l)  A | 
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| tl | Def tl(l) == Case of l; nil  nil ; h.t  t | 
 | |  | Thm*  A:Type, l:A List. tl(l)  A List | 
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| case_inl | Def inl(x) = >  body(x) cont(value,contvalue) == InjCase(value; x. body(x); _. cont(contvalue,contvalue)) | 
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| case_inr | Def inr(x) = >  body(x) cont(value,contvalue) == InjCase(value; _. cont(contvalue,contvalue); x. body(x)) |