let a, b, c, h be Integer; :: thesis: ( h = ((a - b) * (a - c)) * (b - c) implies for S being Sierp45FS of a,b,c st a,b,c are_mutually_distinct holds
for n being Nat st n, numberR (a,b,c) are_congruent_mod 2 & n, numberR0 (a,b,c) are_congruent_mod 3 & ( for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ) holds
a + n,b + n,c + n are_mutually_coprime )

assume A1: h = ((a - b) * (a - c)) * (b - c) ; :: thesis: for S being Sierp45FS of a,b,c st a,b,c are_mutually_distinct holds
for n being Nat st n, numberR (a,b,c) are_congruent_mod 2 & n, numberR0 (a,b,c) are_congruent_mod 3 & ( for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ) holds
a + n,b + n,c + n are_mutually_coprime

let S be Sierp45FS of a,b,c; :: thesis: ( a,b,c are_mutually_distinct implies for n being Nat st n, numberR (a,b,c) are_congruent_mod 2 & n, numberR0 (a,b,c) are_congruent_mod 3 & ( for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ) holds
a + n,b + n,c + n are_mutually_coprime )

assume A2: a,b,c are_mutually_distinct ; :: thesis: for n being Nat st n, numberR (a,b,c) are_congruent_mod 2 & n, numberR0 (a,b,c) are_congruent_mod 3 & ( for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ) holds
a + n,b + n,c + n are_mutually_coprime

let n be Nat; :: thesis: ( n, numberR (a,b,c) are_congruent_mod 2 & n, numberR0 (a,b,c) are_congruent_mod 3 & ( for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ) implies a + n,b + n,c + n are_mutually_coprime )

assume that
A3: n, numberR (a,b,c) are_congruent_mod 2 and
A4: n, numberR0 (a,b,c) are_congruent_mod 3 and
A5: for i being Nat st i in dom S holds
n,S . i are_congruent_mod (Sgm (PrimeDivisors>3 h)) . i ; :: thesis: a + n,b + n,c + n are_mutually_coprime
assume not a + n,b + n,c + n are_mutually_coprime ; :: thesis: contradiction
per cases then ( not a + n,b + n are_coprime or not a + n,c + n are_coprime or not b + n,c + n are_coprime ) ;
end;