theorem splitoptS (G: wff) (a b c: nat) (p: wff):
  $ G -> a = suc c -> p $ >
  $ G -> b = c -> a = suc b -> p $;
    
      
        | Step | Hyp | Ref | Expression | 
        
          | 1 | 
           | 
          hyp h | 
          G -> a = suc c -> p  | 
        
        
          | 2 | 
           | 
          anll | 
          G /\ b = c /\ a = suc b -> G  | 
        
        
          | 3 | 
           | 
          anr | 
          G /\ b = c /\ a = suc b -> a = suc b  | 
        
        
          | 4 | 
           | 
          anlr | 
          G /\ b = c /\ a = suc b -> b = c  | 
        
        
          | 5 | 
          4 | 
          suceqd | 
          G /\ b = c /\ a = suc b -> suc b = suc c  | 
        
        
          | 6 | 
          3, 5 | 
          eqtrd | 
          G /\ b = c /\ a = suc b -> a = suc c  | 
        
        
          | 7 | 
          1, 2, 6 | 
          sylc | 
          G /\ b = c /\ a = suc b -> p  | 
        
        
          | 8 | 
          7 | 
          exp | 
          G /\ b = c -> a = suc b -> p  | 
        
        
          | 9 | 
          8 | 
          exp | 
          G -> b = c -> a = suc b -> p  | 
        
      
    
    Axiom use
    axs_prop_calc
     (ax_1,
      ax_2,
      ax_3,
      ax_mp),
    
axs_pred_calc
     (ax_gen,
      ax_4,
      ax_5,
      ax_6,
      ax_7),
    
axs_peano
     (peano2)