## TPTP Axioms File: LCL013^1.ax

```%------------------------------------------------------------------------------
% File     : LCL013^1 : TPTP v7.5.0. Released v4.0.0.
% Domain   : Logic Calculi (Modal logic)
% Axioms   : Modal logic K
% Version  : [Ben09] axioms.
% English  : Embedding of monomodal logic K in simple type theory.

% Refs     : [Ben09] Benzmueller (2009), Email to Geoff Sutcliffe
% Source   : [Ben09]
% Names    :

% Status   : Satisfiable
% Syntax   : Number of formulae    :    5 (   0 unit;   3 type;   2 defn)
%            Number of atoms       :   30 (   2 equality;   5 variable)
%            Maximal formula depth :    9 (   5 average)
%            Number of connectives :    8 (   1   ~;   1   |;   0   &;   6   @)
%                                         (   0 <=>;   0  =>;   0  <=;   0 <~>)
%                                         (   0  ~|;   0  ~&;   0  !!;   0  ??)
%            Number of type conns  :   10 (  10   >;   0   *;   0   +)
%            Number of symbols     :    6 (   3   :;   0  :=)
%            Number of variables   :    4 (   0 sgn;   1   !;   0   ?;   3   ^)
%                                         (   4   :;   0  :=;   0  !>;   0  ?*)
% SPC      :

%------------------------------------------------------------------------------
%----We reserve an accessibility relation constant rel_k
thf(rel_k_type,type,(
rel_k: \$i > \$i > \$o )).

%----We define mbox_k and mdia_k based on rel_k
thf(mbox_k_type,type,(
mbox_k: ( \$i > \$o ) > \$i > \$o )).

thf(mbox_k,definition,
( mbox_k
= ( ^ [Phi: \$i > \$o,W: \$i] :
! [V: \$i] :
( ~ ( rel_k @ W @ V )
| ( Phi @ V ) ) ) )).

thf(mdia_k_type,type,(
mdia_k: ( \$i > \$o ) > \$i > \$o )).

thf(mdia_k,definition,
( mdia_k
= ( ^ [Phi: \$i > \$o] :
( mnot @ ( mbox_k @ ( mnot @ Phi ) ) ) ) )).

%------------------------------------------------------------------------------
```