TPTP Documents File: SZSOntology


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The SZS success ontology provides status values to describe what is known or 
has been successfully established about the relationship between the axioms and
conjecture in logical data. The SZS no-success ontology provides status values 
to describe why a success ontology value has not been established. The SZS 
dataform ontology provides status values to describe the nature of logical data.
All status values are expressed as "OneWord" to make system output parsing
simple, and also have a three letter mnemonic.

Commonly Used Ontology Values
-----------------------------
The ontologies are very fine grained ontology, which have more status values 
and dataforms than are commonly used by ATP systems. Suitable subsets for 
practical purposes are as follows:
+ For Success
  - FOF problems with a conjecture - report Theorem or CounterSatisfiable
  - FOF problems without a conjecture - report Satisfiable or Unsatisfiable
  - CNF problems - report Satisfiable or Unsatisfiable
+ For No-success
  - System stopped due to CPU limit - report Timeout
  - System gave up due to incompleteness - report GaveUp
  - System stopped due to an error - report Error
+ For Dataforms
  - A generic proof - report Proof
  - A CNF refutation - report CNFRefutation
  - A generic model - report Model
  - A finite model - report FiniteModel
  - An infinite model - report InfiniteModel
  - A saturation - report Saturation

Success ontology values are also used in TPTP format proofs to record the 
relationship between the parents and inferred formula of each inference step.
Commonly used values are:
  - The inferred formula is a theorem of the parents (logical consequences, 
    e.g., resolvants, etc.) - report Theorem
  - The inferred and parent formulae are equisatisfiable (e.g., Skolemization)
    - report EquiSatisfiable
  - The negation of the inferred formula is a theorem of the parents (e.g.,
    negating the conjecture in a proof by refutation) - report CounterTheorem

Standard Presentation of Ontology Values
----------------------------------------
The solution status should be reported in a line starting "% SZS status"
(the leading '%' makes the line into a TPTP language comment). For examples:

    % SZS status Unsatisfiable for SYN075+1

    % SZS status GaveUp for SYN075+1

A success or no-success ontology value should be presented as early as
possible, at least before any data output to justify the value. The justifying 
data should be delimited by lines starting "% SZS output start" and 
"% SZS output end". For example:

    % SZS output start CNFRefutation for SYN075-1
      ...
    % SZS output end CNFRefutation for SYN075-1

All "SZS" lines lines can optionally have software specific information
appended, separated by a :. For examples:

    % SZS status GaveUp for SYN075+1 : Could not complete CNF conversion

    % SZS output end CNFRefutation for SYN075-1 : Completed in CNF conversion

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The SZS Success Ontology
------------------------

The ontology assumes that the input is a 2-tuple of the form <Ax, C>, where 
Ax is a set (conjunction) of axioms and C is a single conjecture formula. This 
is a common standard usage of ATP systems. If the input is not of the form 
<Ax, C>, it is treated as a conjecture formula (even if it is a "set of axioms"
from the user view point, e.g., a set of formulae all with the TPTP role 
"axiom"), and the 2-tuple is <TRUE, C>. The ontology values can also be 
interpreted in terms of the formula F, of the form Ax => C. The ontology values
are based on the possible relationships between the sets of models of Ax and C.
In the figure below many of the "OneWord" status values are abbreviated - see
the list below for the official full "OneWord"s. The lines in the ontology can 
be followed up the hierarchy as isa links, e.g., an ETH isa EQV isa (SAT and
a THM).

                                     Success
                                       SUC
           _____________________________|_____________________________
          |            |                                 |            |
         UNP          SAP                               CSP          CUP
  from____|__________/ |                                 | \__________|___from
  CSA     |            |                                 |            |    SAT
       EquSat          |                                 |        EquCtrSat
   to    ESA           |                                 |           ECS    to
   CUP____|            |                                 |            |____UNP
       Sat'ble      Theorem                           CtrThm       CtrSat
         SAT          THM                               CTH          CSA
          | \_________.|._______________________________.|._________/ |
          |     |      |                |                |            |
          |  FinSat    |             NoConq              |     FinUns |
          |    FSA     |_________      NOC      _________|        FUN |
         _|____________|_        \_____________/        _|____________|_
        |       |        |              |              |        |   ^   |
     Eqvlnt   TautC    WeakC         CtraAx          WeakCC  UnsCon |CtrEqu
       EQV     TAC      WEC            CAX            WCC      UNC  |  CQE
      __|___   _|__   ___|__         ___|___         __|___   __|_  |___|__
     |      | /    \ |      |       |       |       |      | /    \ |      |
  Equiv   Taut-   Weaker  Weaker  SatCon  SatCCo  Weaker  Weaker  Unsat  Equiv
   Thm    ology   TautCo  TautCo  CtraAx  CtraAx  CtrThm  UnsCon  -able  CtrTh
   ETH     TAU     WTC     WTH     SCA     SCC     WCT     WUC     UNS     ECT
                                  __|__    _|___
                                 |     \  /     |
                              TauCon   WCon   UnsCon
                              CtraAx  CtraAx  CtraAx
                               TCA     WCA     UCA
 

+ Success (SUC):
  The logical data has been processed successfully.

+ UnsatisfiabilityPreserving (UNP):
  If there does not exist a model of Ax then there does not exist a model of 
  C, i.e., if Ax is unsatisfiable then C is unsatisfiable.

+ SatisfiabilityPreserving (SAP):
  If there exists a model of Ax then there exists a model of C, i.e., if Ax 
  is satisfiable then C is satisfiable.
  - F is satisfiable.

+ EquiSatisfiable (ESA):
  There exists a model of Ax iff there exists a model of C, i.e., Ax is 
  (un)satisfiable iff C is (un)satisfiable.

+ Satisfiable (SAT):
  Some interpretations are models of Ax, and
  some models of Ax are models of C.
  - F is satisfiable, and ~F is not valid.
  - Possible dataforms are Models of Ax | C.

+ FinitelySatisfiable (FSA):
  Some finite interpretations are finite models of Ax, and
  some finite models of Ax are finite models of C.
  - F is satisfiable, and ~F is not valid.
  - Possible dataforms are FiniteModels of Ax | C.

+ Theorem (THM):
  All models of Ax are models of C.
  - F is valid, and C is a theorem of Ax.
  - Possible dataforms are Proofs of C from Ax.

+ Equivalent (EQV):
  Some interpretations are models of Ax,
  all models of Ax are models of C, and
  all models of C are models of Ax.
  - F is valid, C is a theorem of Ax, and Ax is a theorem of C.
  - Possible dataforms are Proofs of C from Ax and of Ax from C.

+ TautologousConclusion (TAC):
  Some interpretations are models of Ax, and
  all interpretations are models of C.
  - F is valid, and C is a tautology.
  - Possible dataforms are Proofs of C.

+ WeakerConclusion (WEC):
  Some interpretations are models of Ax,
  all models of Ax are models of C, and
  some models of C are not models of Ax.
  - See Theorem and Satisfiable.

+ EquivalentTheorem (ETH):
  Some, but not all, interpretations are models of Ax,
  all models of Ax are models of C, and
  all models of C are models of Ax.
  - See Equivalent.

+ Tautology (TAU):
  All interpretations are models of Ax, and
  all interpretations are models of C.
  - F is valid, ~F is unsatisfiable, and C is a tautology.
  - Possible dataforms are Proofs of Ax and of C.

+ WeakerTautologousConclusion (WTC):
  Some, but not all, interpretations are models of Ax, and
  all interpretations are models of C.
  - F is valid, and C is a tautology.
  - See TautologousConclusion and WeakerConclusion.

+ WeakerTheorem (WTH):
  Some interpretations are models of Ax,
  all models of Ax are models of C,
  some models of C are not models of Ax, and
  some interpretations are not models of C.
  - See Theorem and Satisfiable.

+ ContradictoryAxioms (CAX):
  No interpretations are models of Ax.
  - F is valid, and anything is a theorem of Ax.
  - Possible dataforms are Refutations of Ax.

+ SatisfiableConclusionContradictoryAxioms (SCA):
  No interpretations are models of Ax, and
  some interpretations are models of C.
  - See ContradictoryAxioms.

+ TautologousConclusionContradictoryAxioms (TCA):
  No interpretations are models of Ax, and
  all interpretations are models of C.
  - See TautologousConclusion and SatisfiableConclusionContradictoryAxioms.

+ WeakerConclusionContradictoryAxioms (WCA):
  No interpretations are models of Ax, and
  some, but not all, interpretations are models of C.
  - See SatisfiableConclusionContradictoryAxioms and
    SatisfiableCounterConclusionContradictoryAxioms.

+ CounterUnsatisfiabilityPreserving (CUP):
  If there does not exist a model of Ax then there does not exist a model of 
  ~C, i.e., if Ax is unsatisfiable then ~C is unsatisfiable.

+ CounterSatisfiabilityPreserving (CSP):
  If there exists a model of Ax then there exists a model of ~C, i.e., if Ax 
  is satisfiable then ~C is satisfiable.

+ EquiCounterSatisfiable (ECS):
  There exists a model of Ax iff there exists a model of ~C, i.e., Ax is 
  (un)satisfiable iff ~C is (un)satisfiable.

+ CounterSatisfiable (CSA):
  Some interpretations are models of Ax, and
  some models of Ax are models of ~C.
  - F is not valid, ~F is satisfiable, and C is not a theorem of Ax.
  - Possible dataforms are Models of Ax | ~C.

+ CounterTheorem (CTH):
  All models of Ax are models of ~C.
  - F is not valid, and ~C is a theorem of Ax.
  - Possible dataforms are Proofs of ~C from Ax.

+ CounterEquivalent (CEQ):
  Some interpretations are models of Ax,
  all models of Ax are models of ~C, and
  all models of ~C are models of Ax
  (i.e., all interpretations are models of Ax xor of C).
  - F is not valid, and ~C is a theorem of Ax. 
  - Possible dataforms are Proofs of ~C from Ax and of Ax from ~C.

+ UnsatisfiableConclusion (UNC):
  Some interpretations are models of Ax, and
  all interpretations are models of ~C 
  (i.e., no interpretations are models of C).
  - F is not valid, and ~C is a tautology.
  - Possible dataforms are Proofs of ~C.

+ WeakerCounterConclusion (WCC):
  Some interpretations are models of Ax, and
  all models of Ax are models of ~C, and
  some models of ~C are not models of Ax.
  - See CounterTheorem and CounterSatisfiable.

+ EquivalentCounterTheorem (ECT):
  Some, but not all, interpretations are models of Ax,
  all models of Ax are models of ~C, and
  all models of ~C are models of Ax.
  - See CounterEquivalent.

+ FinitelyUnsatisfiable (FUN):
  All finite interpretations are finite models of Ax, and
  all finite interpretations are finite models of ~C
  (i.e., no finite interpretations are finite models of C).

+ Unsatisfiable (UNS):
  All interpretations are models of Ax, and
  all interpretations are models of ~C.
  (i.e., no interpretations are models of C).
  - F is unsatisfiable, ~F is valid, and ~C is a tautology.
  - Possible dataforms are Proofs of Ax and of C, and Refutations of F.

+ WeakerUnsatisfiableConclusion (WUC):
  Some, but not all, interpretations are models of Ax, and
  all interpretations are models of ~C.
  - See Unsatisfiable and WeakerCounterConclusion.

+ WeakerCounterTheorem (WCT):
  Some interpretations are models of Ax,
  all models of Ax are models of ~C,
  some models of ~C are not models of Ax, and
  some interpretations are not models of ~C.
  - See CounterSatisfiable.

+ SatisfiableCounterConclusionContradictoryAxioms (SCC):
  No interpretations are models of Ax, and
  some interpretations are models of ~C.
  - See ContradictoryAxioms.

+ UnsatisfiableConclusionContradictoryAxioms (UCA):
  No interpretations are models of Ax, and
  all interpretations are models of ~C
  (i.e., no interpretations are models of C).
  - See UnsatisfiableConclusion and
  - SatisfiableCounterConclusionContradictoryAxioms.

+ NoConsequence (NOC):
  Some interpretations are models of Ax,
  some models of Ax are models of C, and
  some models of Ax are models of ~C.
  - F is not valid, F is satisfiable, ~F is not valid, ~F is satisfiable, and 
    C is not a theorem of Ax.
  - Possible dataforms are pairs of models, one Model of Ax | C and one Model 
    of Ax | ~C.

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The NoSuccess Ontology
----------------------

In order to understand and make productive use of a lack of success, it is 
necessary to precisely specify the reason for and nature of the lack of 
success. The SZS no-success ontology provides status values for describing the
reasons. Note that no-success is not the same as failure: failure means that 
the software has completed its attempt to process the logical data and could 
not establish a success ontology value. In contrast, no-success might be 
because the software is still running, or that it has not yet even started 
processing the logical data. In the figure below many of the "OneWord" status 
values are abbreviated - see the list below for the official full "OneWord"s.

                                             NoSuccess
                                                NOS
                             ____________________|___________________
                            |                    |                   |
                          Open                Unknown             Assumed
                           OPN                  UNK             ASS(UNK,SUC)
                                _________________|_________________
                               |                 |                 |
                            Stopped         InProgress         NotTried
                              STP               INP               NTT
           ____________________|________________               ____|____
          |                    |                |             |         |
        Error               Forced           GaveUp           |    NotTriedYet
         ERR                  FOR              GUP            |        NTY
      ____|____            ____|____   _________|__________   |
     |         |          |         | |         |     |    |  |
  OSError   InputEr      User   ResourceOut  Incompl  |  Inappro
    OSE       INE        USR        RSO        INC    |    IAP
           ____|____              ___|___             v
          |         |            |       |           to
       SynError  SemError     Timeout MemyOut        ERR
         SYE       SEE          TMO     MMO
                    |
                TypeError
                   TYE


+ NoSuccess (NOS):
  The logical data has not been processed successfully (yet).

+ Open (OPN):
  A success value has never been established.

+ Unknown (UNK):
  Success value unknown, and no assumption has been made.

+ Assumed (ASS(U,S)):
  The success ontology value S has been assumed because the actual value is 
  unknown for the no-success ontology reason U. U is taken from the 
  subontology starting at Unknown in the no-success ontology.

+ Stopped (STP):
  Software attempted to process the data, and stopped without a success status.

+ Error (ERR):
  Software stopped due to an error.

+ OSError (OSE):
  Software stopped due to an operating system error.

+ InputError (INE):
  Software stopped due to an input error.

+ SyntaxError (SYE):
  Software stopped due to an input syntax error.

+ SemanticError (SEE):
  Software stopped due to an input semantic error.

+ TypeError (TYE):
  Software stopped due to an input type error (for typed logical data).

+ Forced (FOR):
  Software was forced to stop by an external force.

+ User (USR):
  Software was forced to stop by the user.

+ ResourceOut (RSO):
  Software stopped because some resource ran out.

+ Timeout (TMO):
  Software stopped because the CPU time limit ran out.

+ MemoryOut (MMO):
  Software stopped because the memory limit ran out.

+ GaveUp (GUP):
  Software gave up of its own accord.

+ Incomplete (INC):
  Software gave up because it's incomplete.

+ Inappropriate (IAP):
  Software gave up because it cannot process this type of data.

+ InProgress (INP):
  Software is still running.

+ NotTried (NTT):
  Software has not tried to process the data.

+ NotTriedYet (NTY):
  Software has not tried to process the data yet, but might in the future.

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The Dataform Ontology
---------------------

The dataform ontology provides suitable values for describing the form of 
logical data. The ontology values are commonly used to describe data provided
to justify a success ontology value, e.g., if an ATP system reports the success
ontology value Theorem it might output a proof to justify that. In the figure 
below many of the "OneWord" status values are abbreviated - see the list below 
for the official full "OneWord"s.


                                        LogicalData
                                            LDa
                    _________________________|________________________
                   |          |                                       |
                 None     Solution                                 NotSoln
                  Non        Sol                                     NSo
           ___________________|__________________                  ___|____
          |                   |                  |                |        |
       Proof           Interpretation        ListFrm           Assure   IncoPrf
        Prf                  Int                Lof              Ass      IPr
      ___|___                _|_____________     |________________         |
     |       |              |               |    |   |      |     |     IncoRef
  Derivn  Refutn         DomInt           Model  | LiTHF LiFOF LiCNF      IRf
    Der     Ref            Din             Mod   |  Lth    Lfo   Lcn       |
             |        ______|___________   _|__  |                      InCNFRe
          CNFRef     |      |      |    \ |    \ |                        ICf
            CRf   FinInt InfInt HerInt DomMod Saturn 
                    FIn    IIn    HIn    DMo    Sat
                     |  __________________|
                     | /    ^ /    ^ /
                  FinMod InfMod HerMod
                    FMo    IMo    HMo


+ LogicalData (LDa):
  Logical data.

+ Solution (Sln):
  A solution.

+ Proof (Prf):
  A proof.

+ Derivation (Der):
  A derivation (inference steps ending in the theorem, in the Hilbert style).

+ Refutation (Ref):
  A refutation (starting with Ax U ~C and ending in FALSE).

+ CNFRefutation (CRf):
  A refutation in clause normal form, including, for FOF Ax or C, the 
  translation from FOF to CNF (without the FOF to CNF translation it's an 
  IncompleteRefutation).

+ Interpretation (Int):
  An interpretation.

+ DomainInterpretation (DIn):
  An interpretation expressed as a domain, a mapping for functions, and a 
  relation for predicates.

+ FiniteInterpretation (FIn):
  A domain interpretation with a finite domain.

+ InfiniteInterpretation (IIn):
  A domain interpretation with an infinite domain.

+ HerbrandInterpretation (HIn):
  A Herbrand interpretation.

+ Model (Mod):
  A model.

+ DomainModel (DMo):
  A model expressed as a domain, a mapping for functions, and a relation for 
  predicates.

+ FiniteModel (FMo):
  A domain model with a finite domain.

+ InfiniteModel (IMo):
  A domain model with an infinite domain.

+ HerbrandModel (HMo):
  A Herbrand model.

+ Saturation (Sat):
  A model expressed as a saturating set of formulae.

+ ListOfFormulae (Lof):
  A list of formulae.

+ ListOfTHF (Lth):
  A list of THF formulae.

+ ListOfFOF (Lfo):
  A list of FOF formulae.

+ ListOfCNF (Lcn):
  A list of CNF formulae.

+ IncompleteProof (IPr):
  A proof with part missing.

+ IncompleteRefutation (IRf):
  A refutation with parts missing.

+ IncompleteCNFRefutation (ICf):
  A CNF refutation with parts missing.

+ Assurance (Ass):
  Only an assurance of the success ontology value.

+ None (Non):
  Nothing.

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