theorem sappslamed (B: set) (G: wff) (a: nat) {x: nat} (A: set x):
  $ G /\ x = a -> A == B $ >
  $ G -> (\\ x, A) @@ a == B $;
    
      
        | Step | Hyp | Ref | Expression | 
        
          | 1 | 
           | 
          sappslams | 
          (\\ x, A) @@ a == S[a / x] A  | 
        
        
          | 2 | 
           | 
          ax_6 | 
          E. x x = a  | 
        
        
          | 3 | 
           | 
          nfv | 
          F/ x G  | 
        
        
          | 4 | 
           | 
          nfsbs1 | 
          FS/ x S[a / x] A  | 
        
        
          | 5 | 
           | 
          nfsv | 
          FS/ x B  | 
        
        
          | 6 | 
          4, 5 | 
          nfeqs | 
          F/ x S[a / x] A == B  | 
        
        
          | 7 | 
           | 
          sbsq | 
          x = a -> A == S[a / x] A  | 
        
        
          | 8 | 
          7 | 
          anwr | 
          G /\ x = a -> A == S[a / x] A  | 
        
        
          | 9 | 
           | 
          hyp h | 
          G /\ x = a -> A == B  | 
        
        
          | 10 | 
          8, 9 | 
          eqstr3d | 
          G /\ x = a -> S[a / x] A == B  | 
        
        
          | 11 | 
          10 | 
          exp | 
          G -> x = a -> S[a / x] A == B  | 
        
        
          | 12 | 
          3, 6, 11 | 
          eexdh | 
          G -> E. x x = a -> S[a / x] A == B  | 
        
        
          | 13 | 
          2, 12 | 
          mpi | 
          G -> S[a / x] A == B  | 
        
        
          | 14 | 
          1, 13 | 
          syl5eqs | 
          G -> (\\ x, A) @@ a == B  | 
        
      
    
    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)