Skip to content
Projects
Groups
Snippets
Help
Loading...
Help
Submit feedback
Contribute to GitLab
Sign in
Toggle navigation
D
dktactics
Project
Project
Details
Activity
Releases
Cycle Analytics
Repository
Repository
Files
Commits
Branches
Tags
Contributors
Graph
Compare
Charts
Issues
0
Issues
0
List
Board
Labels
Milestones
Merge Requests
0
Merge Requests
0
CI / CD
CI / CD
Pipelines
Jobs
Schedules
Charts
Wiki
Wiki
Snippets
Snippets
Members
Members
Collapse sidebar
Close sidebar
Activity
Graph
Charts
Create a new issue
Jobs
Commits
Issue Boards
Open sidebar
Raphael CAUDERLIER
dktactics
Commits
96747e72
Commit
96747e72
authored
Jan 23, 2018
by
Raphael Cauderlier
Browse files
Options
Browse Files
Download
Email Patches
Plain Diff
Description of the resolution module
parent
3efe270e
Changes
1
Hide whitespace changes
Inline
Side-by-side
Showing
1 changed file
with
57 additions
and
1 deletion
+57
-1
resolution.dk
meta/resolution.dk
+57
-1
No files found.
meta/resolution.dk
View file @
96747e72
...
...
@@ -7,6 +7,50 @@
(setq-local dedukti-compile-options '("-nc" "-e" "-nl" "-I" "../fol"))
;)
(; This module defines tactics corresponding to resolution certificates.
The resolution calculus is a proof calculus for showing the
inconsistency of a conjunction of clauses. The calculus contains
only two rules (on implicitely quantified clauses modulo AC for ∨):
C₁ ∨ l₁ C₂ ∨ ¬l₂ σ = mgu(l₁, l₂)
——————————————————–——————————————————– Resolution
(C₁ ∨ C₂)σ
C ∨ l₁ ∨ l₂ σ = mgu(l₁, l₂)
—————————————————————————————– Factorisation
(C ∨ l₁)σ
The choice of the most general unifier is here to ensure
completeness of the calculus. In our case, we are only interested
in its correctness so if the substitution is provided in the
certificate, we do not need to check it is actually the most
general. Moreover, we can further decompose the rules to simplify
them:
C
————–— Instantiation
Cσ
C₁ ∨ l C₂ ∨ ¬l
————————————————— Propositional resolution
C₁ ∨ C₂
C ∨ l ∨ l
————————– Propositional factorisation
C ∨ l
The Otter prover for example is able to give this level of detail
;)
def prop := fol.prop.
def proof := fol.proof.
def not := fol.not.
...
...
@@ -38,6 +82,14 @@ def resolution (C1 : prop) (C2 : prop)
(Hl => fol.false_elim (or C1 C2) (Hnl Hl))).
(; goal is a disjunction containing A, a proof of A is in context ;)
(; Reasoning modulo AC for ∨ ;)
(; We define a certificate for C₁ ⊢ C₂ when C₁ =_AC C₂ ;)
(; In fact it is even a bit more powerful since it only requires C₂ ⊂
C₁ (set inclusion). ;)
(; Remark: this is highly non deterministic and can thus be slow; to speed up,
we could take as argument a mapping from the disjuncts of C₂ to the one of C₁ ;)
(; Proves Aₖ |- A₁ ∨ … ∨ Aₙ ;)
def modulo_ac_base : certificate
:=
cert.repeat (t =>
...
...
@@ -48,6 +100,9 @@ def modulo_ac_base : certificate
(; A and Goal are disjunctions such that each part of A appears in Goal.
A is an assumption. ;)
(; We apply all possible ∨-left rules on one non-deterministically
chosen assumption and then modulo_ac_base. ;)
def modulo_ac : certificate :=
cert.repeat (mac =>
cert.with_assumption (A => a =>
...
...
@@ -55,6 +110,7 @@ def modulo_ac : certificate :=
(A1 => A2 =>
cert.destruct_or A1 A2
(cert.exact A a)
(; clear A = A₁∨A₂ to avoid looping ;)
(cert.intro (cert.clear A mac))
(cert.intro (cert.clear A mac)))
modulo_ac_base)).
...
...
@@ -106,7 +162,7 @@ def qclause_to_prop : qclause -> prop.
def prop_to_qclause_to_prop : A : prop -> proof A -> proof (qclause_to_prop (prop_to_qclause A)).
[] prop_to_qclause_to_prop (fol
(; [] prop_to_qclause_to_prop (fol ;)
(; a quantified biclause is a universally quantified pair of clauses.
The important fact is that the universal quantification is above
...
...
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment