The inverse does not extend continuously across singular matrices
Statement
Show that there is no continuous map with for every invertible .
Hint
Look at the matrices as .
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Solution
Idea. A continuous map is bounded on a neighbourhood of any point, but the inverse blows up as we approach a singular matrix.
Step 1: suppose exists. Then is continuous at , so there are and with whenever (norm of your choice).
Step 2: test matrices. For the matrix is invertible with , and
This tends to as , contradicting .
Remark. The same argument works at any singular matrix . Choose with . Then , so for small (where is invertible) , hence . So the inverse cannot be extended continuously to any point of the singular set: is the maximal domain on which inversion is continuous (in the sense of extension to a larger set of limit points).
Lesson. Unboundedness near a point kills any continuous extension.