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(*  The Why3 Verification Platform   /   The Why3 Development Team  *)
(*  Copyright 2010-2024 --  Inria - CNRS - Paris-Saclay University  *)
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(*  This software is distributed under the terms of the GNU Lesser  *)
(*  General Public License version 2.1, with the special exception  *)
(*  on linking described in file LICENSE.                           *)
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val abstraction : (Term.lsymbol -> bool) -> Task.task Trans.trans
(** [abstract keep t] applies variable abstraction of the task [t],
    that is replaces subterms or subformulas headed by a logic symbol
    f that do not satisfies [keep f] into a fresh variable.

    Notice that the numeric constants are always kept

    Example (approximate syntax):

    [abstraction (fun f -> List.mem f ["+";"-"]) "goal x*x+y*y = 1"]
    returns ["logic abs1 : int; logic abs2 : int; goal abs1+abs2 = 1"]
*)
