
ALT Rectangle diagram titled “All 3D topological phases in K-theory.” A large yellow rectangle represents 2D topological invariants and is divided into three columns: Gapless, TI/TSC, and Atomic states. Inside it is a smaller orange rectangle (1D invariants), with a red-and-orange striped region within labeled "Symmetry indicators.” A small green rectangle (3D invariants) sits on top of the TI/TSC column. A legend on the right identifies each color: red for 0D, orange for 1D, yellow for 2D, and green for 3D invariants.

ALT In a sense a child does not long for fairy land as a boy longs to be the hero of the first eleven. Does anyone suppose that he really and prosaically longs for all the dangers and discomforts of a fairy tale?—really wants dragons in contemporary England? It is not so. It would be much truer to say that fairy land arouses a longing for he knows not what. It stirs and troubles him (to his life-long enrichment) with the dim sense of something beyond his reach and, far from dulling or emptying the actual world, gives it a new dimension of depth. He does not despise real woods because he has read of enchanted woods: the reading makes all real woods a little enchanted. This is a special kind of longing.
















