In commercial transactions, it frequently happens that two persons are each other's creditors. One example is the building owner-contractor relationship in which a claim by the contractor for payment of his works clashes with a claim by the building owner for compensation for non-performance (e.g. defects, late payments, etc.). A technique that is then often applied is that of set-off: the mutual claims are extinguished to the extent of the smallest amount and only the remaining balance must (effectively) be paid.
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