# Instantons as a -1 dimensional object

I don't know much about Instantons, and looking through the Wiki page it seems like one must have a lot of knowledge about QFT to understand them. However recently I've encountered a statement (which I cannot refer to or extract more information) that instantons are "-1 dimensional" objects in the context of string theory.

The explanation is that if a 0-dimensional object (pointlike-particle) creates 1D worldline the spacetime, the 1-dimensional object (string) creates 2D worldsheet in the spacetime, instanton can create 0D-event(s) in spacetime.

• How can it be a -1 dimensional object? Can you explain it in more details?

• Are there any materials about instantons (which deals with some simple technical aspects) you can present?

Where a string carves out a $2$-dimensional world-sheet and a point particle carves out a $1$-dimensional world-line of spacetime, the instanton carves out a $0$-dimensional world-point. Counting only spatial dimensions, a string is $1$-dimensional and a point particle is $0$-dimensional. By logical extension, an instanton has dimension $-1$, if we only count spatial dimensions; intuitively because, except for an single instant of time, it is not there.