theorem rappsabed1 (F: set) (G P: wff) (a: nat) {x: nat} (A: set x):
  $ G /\ x = a -> F @' a == A -> P $ >
  $ G -> F == S\ x, A -> P $;
    
      
        | Step | Hyp | Ref | Expression | 
        
          | 1 | 
           | 
          ax_6 | 
          E. x x = a  | 
        
        
          | 2 | 
           | 
          nfv | 
          F/ x G  | 
        
        
          | 3 | 
           | 
          nfsv | 
          FS/ x F  | 
        
        
          | 4 | 
           | 
          nfsab1 | 
          FS/ x S\ x, A  | 
        
        
          | 5 | 
          3, 4 | 
          nfeqs | 
          F/ x F == S\ x, A  | 
        
        
          | 6 | 
           | 
          nfv | 
          F/ x P  | 
        
        
          | 7 | 
          5, 6 | 
          nfim | 
          F/ x F == S\ x, A -> P  | 
        
        
          | 8 | 
           | 
          rappeq1 | 
          F == S\ x, A -> F @' a == (S\ x, A) @' a  | 
        
        
          | 9 | 
          8 | 
          eqseq1d | 
          F == S\ x, A -> (F @' a == A <-> (S\ x, A) @' a == A)  | 
        
        
          | 10 | 
           | 
          rappsab | 
          (S\ x, A) @' x == A  | 
        
        
          | 11 | 
           | 
          anr | 
          G /\ x = a -> x = a  | 
        
        
          | 12 | 
          11 | 
          rappeq2d | 
          G /\ x = a -> (S\ x, A) @' x == (S\ x, A) @' a  | 
        
        
          | 13 | 
          12 | 
          eqscomd | 
          G /\ x = a -> (S\ x, A) @' a == (S\ x, A) @' x  | 
        
        
          | 14 | 
          10, 13 | 
          syl6eqs | 
          G /\ x = a -> (S\ x, A) @' a == A  | 
        
        
          | 15 | 
          9, 14 | 
          syl5ibrcom | 
          G /\ x = a -> F == S\ x, A -> F @' a == A  | 
        
        
          | 16 | 
           | 
          hyp e | 
          G /\ x = a -> F @' a == A -> P  | 
        
        
          | 17 | 
          15, 16 | 
          syld | 
          G /\ x = a -> F == S\ x, A -> P  | 
        
        
          | 18 | 
          17 | 
          exp | 
          G -> x = a -> F == S\ x, A -> P  | 
        
        
          | 19 | 
          2, 7, 18 | 
          eexdh | 
          G -> E. x x = a -> F == S\ x, A -> P  | 
        
        
          | 20 | 
          1, 19 | 
          mpi | 
          G -> F == S\ x, A -> P  | 
        
      
    
    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)