let f be Function of [:NAT,NAT:],ExtREAL; :: thesis: ( ( f is convergent_in_cod1_to_+infty implies - f is convergent_in_cod1_to_-infty ) & ( - f is convergent_in_cod1_to_-infty implies f is convergent_in_cod1_to_+infty ) & ( f is convergent_in_cod1_to_-infty implies - f is convergent_in_cod1_to_+infty ) & ( - f is convergent_in_cod1_to_+infty implies f is convergent_in_cod1_to_-infty ) & ( f is convergent_in_cod1_to_finite implies - f is convergent_in_cod1_to_finite ) & ( - f is convergent_in_cod1_to_finite implies f is convergent_in_cod1_to_finite ) & ( f is convergent_in_cod2_to_+infty implies - f is convergent_in_cod2_to_-infty ) & ( - f is convergent_in_cod2_to_-infty implies f is convergent_in_cod2_to_+infty ) & ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) & ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )
now :: thesis: ( ( f is convergent_in_cod1_to_+infty implies - f is convergent_in_cod1_to_-infty ) & ( - f is convergent_in_cod1_to_-infty implies f is convergent_in_cod1_to_+infty ) )end;
hence ( f is convergent_in_cod1_to_+infty iff - f is convergent_in_cod1_to_-infty ) ; :: thesis: ( ( f is convergent_in_cod1_to_-infty implies - f is convergent_in_cod1_to_+infty ) & ( - f is convergent_in_cod1_to_+infty implies f is convergent_in_cod1_to_-infty ) & ( f is convergent_in_cod1_to_finite implies - f is convergent_in_cod1_to_finite ) & ( - f is convergent_in_cod1_to_finite implies f is convergent_in_cod1_to_finite ) & ( f is convergent_in_cod2_to_+infty implies - f is convergent_in_cod2_to_-infty ) & ( - f is convergent_in_cod2_to_-infty implies f is convergent_in_cod2_to_+infty ) & ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) & ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )
now :: thesis: ( ( f is convergent_in_cod1_to_-infty implies - f is convergent_in_cod1_to_+infty ) & ( - f is convergent_in_cod1_to_+infty implies f is convergent_in_cod1_to_-infty ) )end;
hence ( f is convergent_in_cod1_to_-infty iff - f is convergent_in_cod1_to_+infty ) ; :: thesis: ( ( f is convergent_in_cod1_to_finite implies - f is convergent_in_cod1_to_finite ) & ( - f is convergent_in_cod1_to_finite implies f is convergent_in_cod1_to_finite ) & ( f is convergent_in_cod2_to_+infty implies - f is convergent_in_cod2_to_-infty ) & ( - f is convergent_in_cod2_to_-infty implies f is convergent_in_cod2_to_+infty ) & ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) & ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )
now :: thesis: ( ( f is convergent_in_cod1_to_finite implies - f is convergent_in_cod1_to_finite ) & ( - f is convergent_in_cod1_to_finite implies f is convergent_in_cod1_to_finite ) )end;
hence ( f is convergent_in_cod1_to_finite iff - f is convergent_in_cod1_to_finite ) ; :: thesis: ( ( f is convergent_in_cod2_to_+infty implies - f is convergent_in_cod2_to_-infty ) & ( - f is convergent_in_cod2_to_-infty implies f is convergent_in_cod2_to_+infty ) & ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) & ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )
now :: thesis: ( ( f is convergent_in_cod2_to_+infty implies - f is convergent_in_cod2_to_-infty ) & ( - f is convergent_in_cod2_to_-infty implies f is convergent_in_cod2_to_+infty ) )end;
hence ( f is convergent_in_cod2_to_+infty iff - f is convergent_in_cod2_to_-infty ) ; :: thesis: ( ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) & ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )
now :: thesis: ( ( f is convergent_in_cod2_to_-infty implies - f is convergent_in_cod2_to_+infty ) & ( - f is convergent_in_cod2_to_+infty implies f is convergent_in_cod2_to_-infty ) )end;
hence ( f is convergent_in_cod2_to_-infty iff - f is convergent_in_cod2_to_+infty ) ; :: thesis: ( f is convergent_in_cod2_to_finite iff - f is convergent_in_cod2_to_finite )
now :: thesis: ( ( f is convergent_in_cod2_to_finite implies - f is convergent_in_cod2_to_finite ) & ( - f is convergent_in_cod2_to_finite implies f is convergent_in_cod2_to_finite ) )end;
hence ( f is convergent_in_cod2_to_finite iff - f is convergent_in_cod2_to_finite ) ; :: thesis: verum