Commit 3180aa4b authored by Jean-Christophe Filliâtre's avatar Jean-Christophe Filliâtre
Browse files

gallery: dirichlet renamed into pigeonhole

(there is already something called dirichlet in the gallery)
parent f1363461
......@@ -3,7 +3,7 @@
Proved using a lemma function. *)
module Dirichlet
module Pigeonhole
use import HighOrd
use import int.Int
......@@ -19,7 +19,7 @@ module Dirichlet
variant { n }
= if n = 0 then empty else add (n-1) (below (n-1))
let lemma dirichlet (n m: int) (f: int -> int)
let lemma pigeonhole (n m: int) (f: int -> int)
requires { 0 <= m < n }
requires { forall i. 0 <= i < n -> 0 <= f i < m }
ensures { exists i1, i2. 0 <= i1 < i2 < n /\ f i1 = f i2 }
......@@ -4,44 +4,44 @@
<why3session shape_version="4">
<prover id="0" name="Alt-Ergo" version="0.99.1" timelimit="6" memlimit="1000"/>
<prover id="6" name="Alt-Ergo" version="0.95.1" timelimit="6" memlimit="1000"/>
<file name="../dirichlet.mlw" expanded="true">
<theory name="Dirichlet" sum="8ee565a294b83da869ffcfd8fb11b973" expanded="true">
<file name="../pigeonhole.mlw" expanded="true">
<theory name="Pigeonhole" sum="8ee565a294b83da869ffcfd8fb11b973" expanded="true">
<goal name="WP_parameter below" expl="VC for below" expanded="true">
<proof prover="6"><result status="valid" time="0.01" steps="75"/></proof>
<goal name="WP_parameter dirichlet" expl="VC for dirichlet" expanded="true">
<goal name="WP_parameter pigeonhole" expl="VC for pigeonhole" expanded="true">
<transf name="split_goal_wp" expanded="true">
<goal name="WP_parameter dirichlet.1" expl="1. precondition">
<goal name="WP_parameter pigeonhole.1" expl="1. precondition">
<proof prover="0"><result status="valid" time="0.02" steps="3"/></proof>
<goal name="WP_parameter dirichlet.2" expl="2. assertion">
<goal name="WP_parameter pigeonhole.2" expl="2. assertion">
<proof prover="0"><result status="valid" time="0.01" steps="4"/></proof>
<goal name="WP_parameter dirichlet.3" expl="3. unreachable point">
<goal name="WP_parameter pigeonhole.3" expl="3. unreachable point">
<proof prover="0"><result status="valid" time="0.02" steps="5"/></proof>
<goal name="WP_parameter dirichlet.4" expl="4. loop invariant init">
<goal name="WP_parameter pigeonhole.4" expl="4. loop invariant init">
<proof prover="0"><result status="valid" time="0.01" steps="7"/></proof>
<goal name="WP_parameter dirichlet.5" expl="5. loop invariant init">
<goal name="WP_parameter pigeonhole.5" expl="5. loop invariant init">
<proof prover="0"><result status="valid" time="0.01" steps="8"/></proof>
<goal name="WP_parameter dirichlet.6" expl="6. postcondition">
<goal name="WP_parameter pigeonhole.6" expl="6. postcondition">
<proof prover="6"><result status="valid" time="0.02" steps="22"/></proof>
<goal name="WP_parameter dirichlet.7" expl="7. loop invariant preservation">
<goal name="WP_parameter pigeonhole.7" expl="7. loop invariant preservation">
<proof prover="0"><result status="valid" time="0.01" steps="11"/></proof>
<goal name="WP_parameter dirichlet.8" expl="8. loop invariant preservation">
<goal name="WP_parameter pigeonhole.8" expl="8. loop invariant preservation">
<proof prover="0"><result status="valid" time="0.02" steps="53"/></proof>
<goal name="WP_parameter dirichlet.9" expl="9. precondition">
<goal name="WP_parameter pigeonhole.9" expl="9. precondition">
<proof prover="0"><result status="valid" time="0.00" steps="5"/></proof>
<goal name="WP_parameter dirichlet.10" expl="10. assertion">
<goal name="WP_parameter pigeonhole.10" expl="10. assertion">
<proof prover="0"><result status="valid" time="0.02" steps="28"/></proof>
<goal name="WP_parameter dirichlet.11" expl="11. unreachable point">
<goal name="WP_parameter pigeonhole.11" expl="11. unreachable point">
<proof prover="0"><result status="valid" time="0.01" steps="9"/></proof>
(** Random Access Lists.
(Okasaki, "Purely Functional Data Structures", 10.1.2.)
The code below uses polymorphic recursion (both in the logic
and in the programs).
- induction_ty_lex has no effect on a goal involving polymorphic recursion
- a lemma function is not allowed to perform polymorphic recursion?
Author: Jean-Christophe Filliâtre (CNRS)
module RandomAccessList
......@@ -24,13 +22,13 @@ module RandomAccessList
| Zero (ral ('a, 'a))
| One 'a (ral ('a, 'a))
function flatten (l: list ('a , 'a)) : list 'a
function flatten (l: list ('a, 'a)) : list 'a
= match l with
| Nil -> Nil
| Cons (x, y) l1 -> Cons x (Cons y (flatten l1))
let rec lemma length_flatten (l:list ('a,'a))
let rec lemma length_flatten (l:list ('a, 'a))
ensures { length (flatten l) = 2 * length l }
variant { l }
= match l with
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