theorem sublistAteq3d (_G: wff) (n L1 _L21 _L22: nat):
  $ _G -> _L21 = _L22 $ >
  $ _G -> (sublistAt n L1 _L21 <-> sublistAt n L1 _L22) $;
    
      
        | Step | Hyp | Ref | Expression | 
|---|
        
          | 1 |  | eqidd | _G -> n = n | 
        
          | 2 |  | eqidd | _G -> L1 = L1 | 
        
          | 3 |  | hyp _h | _G -> _L21 = _L22 | 
        
          | 4 | 1, 2, 3 | sublistAteqd | _G -> (sublistAt n L1 _L21 <-> sublistAt n L1 _L22) | 
      
    
    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)