src/HOL/Hyperreal/StarClasses.thy

class instances for nonstandard types

(*  Title       : HOL/Hyperreal/StarClasses.thy
    ID          : $Id$
    Author      : Brian Huffman
*)

header {* Class Instances *}

theory StarClasses
imports Transfer
begin

subsection "HOL.thy"

instance star :: (order) order
apply (intro_classes)
apply (transfer, rule order_refl)
apply (transfer, erule (1) order_trans)
apply (transfer, erule (1) order_antisym)
apply (transfer, rule order_less_le)
done

instance star :: (linorder) linorder
by (intro_classes, transfer, rule linorder_linear)


subsection "LOrder.thy"

text {*
  Some extra trouble is necessary because the class axioms 
  for @{term meet} and @{term join} use quantification over
  function spaces.
*}

lemma ex_star_fun:
  "\<exists>f::('a \<Rightarrow> 'b) star. P (Ifun f)
   \<Longrightarrow> \<exists>f::'a star \<Rightarrow> 'b star. P f"
by (erule exE, erule exI)

lemma ex_star_fun2:
  "\<exists>f::('a \<Rightarrow> 'b \<Rightarrow> 'c) star. P (Ifun2 f)
   \<Longrightarrow> \<exists>f::'a star \<Rightarrow> 'b star \<Rightarrow> 'c star. P f"
by (erule exE, erule exI)

instance star :: (join_semilorder) join_semilorder
apply (intro_classes)
apply (rule ex_star_fun2)
apply (transfer is_join_def)
apply (rule join_exists)
done

instance star :: (meet_semilorder) meet_semilorder
apply (intro_classes)
apply (rule ex_star_fun2)
apply (transfer is_meet_def)
apply (rule meet_exists)
done

instance star :: (lorder) lorder ..

lemma star_join_def: "join \<equiv> Ifun2_of join"
 apply (rule is_join_unique[OF is_join_join, THEN eq_reflection])
 apply (transfer is_join_def, rule is_join_join)
done

lemma star_meet_def: "meet \<equiv> Ifun2_of meet"
 apply (rule is_meet_unique[OF is_meet_meet, THEN eq_reflection])
 apply (transfer is_meet_def, rule is_meet_meet)
done

subsection "OrderedGroup.thy"

instance star :: (semigroup_add) semigroup_add
by (intro_classes, transfer, rule add_assoc)

instance star :: (ab_semigroup_add) ab_semigroup_add
by (intro_classes, transfer, rule add_commute)

instance star :: (semigroup_mult) semigroup_mult
by (intro_classes, transfer, rule mult_assoc)

instance star :: (ab_semigroup_mult) ab_semigroup_mult
by (intro_classes, transfer, rule mult_commute)

instance star :: (comm_monoid_add) comm_monoid_add
by (intro_classes, transfer, rule comm_monoid_add_class.add_0)

instance star :: (monoid_mult) monoid_mult
apply (intro_classes)
apply (transfer, rule mult_1_left)
apply (transfer, rule mult_1_right)
done

instance star :: (comm_monoid_mult) comm_monoid_mult
by (intro_classes, transfer, rule mult_1)

instance star :: (cancel_semigroup_add) cancel_semigroup_add
apply (intro_classes)
apply (transfer, erule add_left_imp_eq)
apply (transfer, erule add_right_imp_eq)
done

instance star :: (cancel_ab_semigroup_add) cancel_ab_semigroup_add
by (intro_classes, transfer, rule add_imp_eq)

instance star :: (ab_group_add) ab_group_add
apply (intro_classes)
apply (transfer, rule left_minus)
apply (transfer, rule diff_minus)
done

instance star :: (pordered_ab_semigroup_add) pordered_ab_semigroup_add
by (intro_classes, transfer, rule add_left_mono)

instance star :: (pordered_cancel_ab_semigroup_add) pordered_cancel_ab_semigroup_add ..

instance star :: (pordered_ab_semigroup_add_imp_le) pordered_ab_semigroup_add_imp_le
by (intro_classes, transfer, rule add_le_imp_le_left)

instance star :: (pordered_ab_group_add) pordered_ab_group_add ..
instance star :: (ordered_cancel_ab_semigroup_add) ordered_cancel_ab_semigroup_add ..
instance star :: (lordered_ab_group_meet) lordered_ab_group_meet ..
instance star :: (lordered_ab_group_meet) lordered_ab_group_meet ..
instance star :: (lordered_ab_group) lordered_ab_group ..

instance star :: (lordered_ab_group_abs) lordered_ab_group_abs
apply (intro_classes)
apply (transfer star_join_def, rule abs_lattice)
done

text "Ring-and-Field.thy"

instance star :: (semiring) semiring
apply (intro_classes)
apply (transfer, rule left_distrib)
apply (transfer, rule right_distrib)
done

instance star :: (semiring_0) semiring_0 ..
instance star :: (semiring_0_cancel) semiring_0_cancel ..

instance star :: (comm_semiring) comm_semiring
by (intro_classes, transfer, rule distrib)

instance star :: (comm_semiring_0) comm_semiring_0 ..
instance star :: (comm_semiring_0_cancel) comm_semiring_0_cancel ..

instance star :: (axclass_0_neq_1) axclass_0_neq_1
by (intro_classes, transfer, rule zero_neq_one)

instance star :: (semiring_1) semiring_1 ..
instance star :: (comm_semiring_1) comm_semiring_1 ..

instance star :: (axclass_no_zero_divisors) axclass_no_zero_divisors
by (intro_classes, transfer, rule no_zero_divisors)

instance star :: (semiring_1_cancel) semiring_1_cancel ..
instance star :: (comm_semiring_1_cancel) comm_semiring_1_cancel ..
instance star :: (ring) ring ..
instance star :: (comm_ring) comm_ring ..
instance star :: (ring_1) ring_1 ..
instance star :: (comm_ring_1) comm_ring_1 ..
instance star :: (idom) idom .. 

instance star :: (field) field
apply (intro_classes)
apply (transfer, erule left_inverse)
apply (transfer, rule divide_inverse)
done

instance star :: (division_by_zero) division_by_zero
by (intro_classes, transfer, rule inverse_zero)

instance star :: (pordered_semiring) pordered_semiring
apply (intro_classes)
apply (transfer, erule (1) mult_left_mono)
apply (transfer, erule (1) mult_right_mono)
done

instance star :: (pordered_cancel_semiring) pordered_cancel_semiring ..

instance star :: (ordered_semiring_strict) ordered_semiring_strict
apply (intro_classes)
apply (transfer, erule (1) mult_strict_left_mono)
apply (transfer, erule (1) mult_strict_right_mono)
done

instance star :: (pordered_comm_semiring) pordered_comm_semiring
by (intro_classes, transfer, rule pordered_comm_semiring_class.mult_mono)

instance star :: (pordered_cancel_comm_semiring) pordered_cancel_comm_semiring ..

instance star :: (ordered_comm_semiring_strict) ordered_comm_semiring_strict
by (intro_classes, transfer, rule ordered_comm_semiring_strict_class.mult_strict_mono)

instance star :: (pordered_ring) pordered_ring ..
instance star :: (lordered_ring) lordered_ring ..

instance star :: (axclass_abs_if) axclass_abs_if
by (intro_classes, transfer, rule abs_if)

instance star :: (ordered_ring_strict) ordered_ring_strict ..
instance star :: (pordered_comm_ring) pordered_comm_ring ..

instance star :: (ordered_semidom) ordered_semidom
by (intro_classes, transfer, rule zero_less_one)

instance star :: (ordered_idom) ordered_idom ..
instance star :: (ordered_field) ordered_field ..

subsection "Power.thy"

text {*
  Proving the class axiom @{thm [source] power_Suc} for type
  @{typ "'a star"} is a little tricky, because it quantifies
  over values of type @{typ nat}. The transfer principle does
  not handle quantification over non-star types in general,
  but we can work around this by fixing an arbitrary @{typ nat}
  value, and then applying the transfer principle.
*}

instance star :: (recpower) recpower
proof
  show "\<And>a::'a star. a ^ 0 = 1"
    by transfer (rule power_0)
next
  fix n show "\<And>a::'a star. a ^ Suc n = a * a ^ n"
    by transfer (rule power_Suc)
qed

subsection "Integ/Number.thy"

lemma star_of_nat_def: "of_nat n \<equiv> star_of (of_nat n)"
by (rule eq_reflection, induct_tac n, simp_all)

lemma int_diff_cases:
assumes prem: "\<And>m n. z = int m - int n \<Longrightarrow> P" shows "P"
 apply (rule_tac z=z in int_cases)
  apply (rule_tac m=n and n=0 in prem, simp)
 apply (rule_tac m=0 and n="Suc n" in prem, simp)
done -- "Belongs in Integ/IntDef.thy"

lemma star_of_int_def: "of_int z \<equiv> star_of (of_int z)"
 apply (rule eq_reflection)
 apply (rule_tac z=z in int_diff_cases)
 apply (simp add: star_of_nat_def)
done

instance star :: (number_ring) number_ring
by (intro_classes, simp only: star_number_def star_of_int_def number_of_eq)

lemma star_of_of_nat [simp]: "star_of (of_nat n) = of_nat n"
by (simp add: star_of_nat_def)

lemma star_of_of_int [simp]: "star_of (of_int z) = of_int z"
by (simp add: star_of_int_def)

end