A smock-faced amoroso.

Instead, mispicks, i.e. large picking errors that occur when ambiguities exist in recognizing the first arrival among multiple events, are expected to produce local artefacts in the final velocity map.

“Okay boys,” I said, in sergeant-majorly style, “there are just two rules that you need to know for this expedition.”

It says that, if A is a singular matrix, then every neighborhood of A contains an invertible matrix. In other words, if A is singular, we can perturb A just a little and obtain an invertible matrix.