theorem inseq1 (_a1 _a2 b: nat): $ _a1 = _a2 -> _a1 ; b = _a2 ; b $;
    
      
        | Step | Hyp | Ref | Expression | 
|---|
        
          | 1 |  | id | _a1 = _a2 -> _a1 = _a2 | 
        
          | 2 | 1 | inseq1d | _a1 = _a2 -> _a1 ; b = _a2 ; b | 
      
    
    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)