pub theorem pr0: $ 0, 0 = 0 $;
    
      
        | Step | Hyp | Ref | Expression | 
|---|
        
          | 1 |  | eqtr | 0, 0 = 0 + 0 -> 0 + 0 = 0 -> 0, 0 = 0 | 
        
          | 2 |  | addeq1 | (0 + 0) * suc (0 + 0) // 2 = 0 -> (0 + 0) * suc (0 + 0) // 2 + 0 = 0 + 0 | 
        
          | 3 | 2 | conv pr | (0 + 0) * suc (0 + 0) // 2 = 0 -> 0, 0 = 0 + 0 | 
        
          | 4 |  | eqtr | (0 + 0) * suc (0 + 0) // 2 = 0 // 2 -> 0 // 2 = 0 -> (0 + 0) * suc (0 + 0) // 2 = 0 | 
        
          | 5 |  | diveq1 | (0 + 0) * suc (0 + 0) = 0 -> (0 + 0) * suc (0 + 0) // 2 = 0 // 2 | 
        
          | 6 |  | eqtr | (0 + 0) * suc (0 + 0) = 0 * suc (0 + 0) -> 0 * suc (0 + 0) = 0 -> (0 + 0) * suc (0 + 0) = 0 | 
        
          | 7 |  | muleq1 | 0 + 0 = 0 -> (0 + 0) * suc (0 + 0) = 0 * suc (0 + 0) | 
        
          | 8 |  | add0 | 0 + 0 = 0 | 
        
          | 9 | 7, 8 | ax_mp | (0 + 0) * suc (0 + 0) = 0 * suc (0 + 0) | 
        
          | 10 | 6, 9 | ax_mp | 0 * suc (0 + 0) = 0 -> (0 + 0) * suc (0 + 0) = 0 | 
        
          | 11 |  | mul01 | 0 * suc (0 + 0) = 0 | 
        
          | 12 | 10, 11 | ax_mp | (0 + 0) * suc (0 + 0) = 0 | 
        
          | 13 | 5, 12 | ax_mp | (0 + 0) * suc (0 + 0) // 2 = 0 // 2 | 
        
          | 14 | 4, 13 | ax_mp | 0 // 2 = 0 -> (0 + 0) * suc (0 + 0) // 2 = 0 | 
        
          | 15 |  | div01 | 0 // 2 = 0 | 
        
          | 16 | 14, 15 | ax_mp | (0 + 0) * suc (0 + 0) // 2 = 0 | 
        
          | 17 | 3, 16 | ax_mp | 0, 0 = 0 + 0 | 
        
          | 18 | 1, 17 | ax_mp | 0 + 0 = 0 -> 0, 0 = 0 | 
        
          | 19 | 18, 8 | ax_mp | 0, 0 = 0 | 
      
    
    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
     (peano1,
      peano2,
      peano5,
      addeq,
      muleq,
      add0,
      addS,
      mul0,
      mulS)