Permanent establishment: fixed business presence or dependent agent activity can create taxable presence under the treaty. Permanent establishment is a fixed place of business where enterprise activities are wholly or partly carried on, including management, branch, office, factory, workshop, warehouse, extraction sites, permanent sales exhibitions, and certain construction or assembly projects exceeding a specified duration. Exclusions apply where facilities are used solely for storage, display, purchasing, information collection, advertising, or scientific research. Dependent agents who habitually negotiate and conclude contracts, maintain stocks for regular delivery, or secure orders predominantly for the enterprise may constitute a permanent establishment. Brokers of genuine independence and mere parent-subsidiary relationships do not by themselves create a permanent establishment.