# Contents

## Idea

The flop transition is a continuous path in a space of noncommutative 2-geometries that starts at an ordinary complex 3-dimensional Calabi-Yau space, then passes through a point that does not correspond to an ordinary geometry (the Gepner point) and emerges afterwards again as an ordinary CY-geometry – but now with different topology.

This was found and discussed in the context of string theory but the phenomenon is a general abstract one in the theory of 2d SCFTs regarded as generalized geometries – as described at 2-spectral triple.

## References

A survey is in

A rough and brief survey of the flop transition and related phenomena with many pointers to original literature is also given in

Revised on March 20, 2014 03:05:52 by Urs Schreiber (89.204.138.150)