In the field of symplectic geometry, a central issue involves how to count the intersection points of two complicated geometric spaces. This counting question is at the heart of one of the most famous ...

Imagine holding a strip of paper. You give it a half-twist and then tape its ends together. The shape you’re now holding is the ticket to a world where surfaces have only one side and boundaries blur ...

Just like a Möbius strip made of paper, when this DNA Möbius strip is cut down the middle, it generates a loop half as narrow and twice as long as the original, with four half turns (a twist of 720o) ...