theorem eqmin1 (a b: nat): $ a <= b -> min a b = a $;
    
      
        | Step | Hyp | Ref | Expression | 
|---|
        
          | 1 |  | leloe | a <= b <-> a < b \/ a = b | 
        
          | 2 |  | eor | (a < b -> min a b = a) -> (a = b -> min a b = a) -> a < b \/ a = b -> min a b = a | 
        
          | 3 |  | ifpos | a < b -> if (a < b) a b = a | 
        
          | 4 | 3 | conv min | a < b -> min a b = a | 
        
          | 5 | 2, 4 | ax_mp | (a = b -> min a b = a) -> a < b \/ a = b -> min a b = a | 
        
          | 6 |  | ifid | if (a < b) a a = a | 
        
          | 7 |  | eqcom | a = b -> b = a | 
        
          | 8 | 7 | ifeq3d | a = b -> if (a < b) a b = if (a < b) a a | 
        
          | 9 | 8 | conv min | a = b -> min a b = if (a < b) a a | 
        
          | 10 | 6, 9 | syl6eq | a = b -> min a b = a | 
        
          | 11 | 5, 10 | ax_mp | a < b \/ a = b -> min a b = a | 
        
          | 12 | 1, 11 | sylbi | a <= b -> min a b = a | 
      
    
    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,
      add0,
      addS)