theorem zlteqd (_G: wff) (_m1 _m2 _n1 _n2: nat):
  $ _G -> _m1 = _m2 $ >
  $ _G -> _n1 = _n2 $ >
  $ _G -> (_m1  _m2 
    
      
        | Step | Hyp | Ref | Expression | 
|---|
        
          | 1 |  | hyp _mh | _G -> _m1 = _m2 | 
        
          | 2 |  | hyp _nh | _G -> _n1 = _n2 | 
        
          | 3 | 1, 2 | zsubeqd | _G -> _m1 -Z _n1 = _m2 -Z _n2 | 
        
          | 4 | 3 | oddeqd | _G -> (odd (_m1 -Z _n1) <-> odd (_m2 -Z _n2)) | 
        
          | 5 | 4 | conv zlt | _G -> (_m1 <Z _n1 <-> _m2 <Z _n2) | 
      
    
    Axiom use
    axs_prop_calc
     (ax_1,
      ax_2,
      ax_3,
      ax_mp,
      itru),
    axs_pred_calc
     (ax_gen,
      ax_4,
      ax_5,
      ax_6,
      ax_7,
      ax_10,
      ax_11,
      ax_12),
    axs_set
     (elab,
      ax_8),
    axs_the
     (theid,
      the0),
    axs_peano
     (peano2,
      addeq,
      muleq)