The addition of rational Cauchy sequences is cancellative, i.e. for all rational Cauchy sequences \((x_n)_{n\in\mathbb N},(y_n)_{n\in\mathbb N},(z_n)_{n\in\mathbb N}\), the following laws (both) are fulfilled:
Left cancellation property: If the equation \((z_n)_{n\in\mathbb N} + (x_n)_{n\in\mathbb N}=(z_n)_{n\in\mathbb N} + (y_n)_{n\in\mathbb N}\) holds, then it implies \((x_n)_{n\in\mathbb N}=(y_n)_{n\in\mathbb N}\).
Right cancellation property: If the equation \((x_n)_{n\in\mathbb N} + (z_n)_{n\in\mathbb N}=(y_n)_{n\in\mathbb N} + (z_n)_{n\in\mathbb N}\) holds, then it implies \((x_n)_{n\in\mathbb N}=(y_n)_{n\in\mathbb N}\).
Conversely, the equation \((x_n)_{n\in\mathbb N}=(y_n)_{n\in\mathbb N}\) implies
for all rational Cauchy sequences \((x_n)_{n\in\mathbb N},(y_n)_{n\in\mathbb N},(z_n)_{n\in\mathbb N}\).
Proofs: 1