Final answer:
Muqarnas is the decorative system in Islamic architecture, characterized by intricate corbeling of brackets and squinches.
Step-by-step explanation:
The system of decoration in Islamic architecture described by the intricate corbeling of brackets, squinches, and inverted pyramids is known as muqarnas. These are ornamental features often found in Islamic architecture that create a sense of transition between different architectural elements, such as between a dome and the supporting walls. The muqarnas structure is highly intricate and creates a three-dimensional effect of cascading arches and niches. The muqarnas can be seen in the minaret, mihrab, and other decorative features in mosques.