theorem ltmin (a b c: nat): $ a < min b c <-> a < b /\ a < c $;
    
      
        | Step | Hyp | Ref | Expression | 
        
          | 1 | 
           | 
          lemin | 
          suc a <= min b c <-> suc a <= b /\ suc a <= c  | 
        
        
          | 2 | 
          1 | 
          conv lt | 
          a < min b c <-> a < b /\ a < c  | 
        
      
    
    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)