Questions about Traversable Wormhole Metric

[space-time]

First of all, the metric I am referring to is this one:

ds²= -c²dt² + dl² + (k² + l²)(dᶿ² + sin²(ᶿ)dø²)

where k is the radius of the throat of the wormhole. (sorry for the small Greek letters)

Now I have two questions about this solution to Einstein's equations:

1. What does the coordinate l represent? All I know is that its domain is all real numbers and negative values of l apparently represents another universe.

2. When this solution was derived, did the equations include the cosmological constant or was that just left out?

 

[bapowell]

1. Looks like $l$ is the radial coordinate.

2. In order for this to be a solution to Einstein's Equations, you need exotic matter that violates the energy conditions. There might be a cosmological constant but its contribution is swamped by that of the exotic matter.