let a, b be Integer; for m, n being non zero Nat holds
( a,b are_coprime iff a |^ m,b |^ n are_coprime )
let m, n be non zero Nat; ( a,b are_coprime iff a |^ m,b |^ n are_coprime )
L1:
( a,b are_coprime implies a |^ m,b |^ n are_coprime )
( a |^ m,b |^ n are_coprime implies a,b are_coprime )
hence
( a,b are_coprime iff a |^ m,b |^ n are_coprime )
by L1; verum