Explain cantilever construction. Is the structure below an example of cantilever construction? Why/why not?

This is an example of a vault, specifically a barrel vault. This type of construction is very stable because of its weight bearing capacity. Therefore the structure is likely to be long-lasting.

The cantilever is a type of structural element whose set of conditions is limited to the restriction of the translations of one end, which are associated with the restriction of the rotations of that same section, known as embedding or setting, the imposition of relative displacements or the imposition of elastic supports. In a nutshell, it features a horizontal beam that extends past its vertical support. Sure, this structure is an example of cantilever construction. You can see the horizontal beams of the roof and base extend past the vertical supports, creating a unique design.