Non-invertible are excluded "because" otherwise it would not form a group (every element must have an inverse). This is therefore the largest possible group under matrix multiplication, other matrix multiplication groups being subgroups of it.
The General Linear Group, denoted as \( \text{GL}(n, F) \), is a fundamental concept in linear algebra and group theory. It consists of all invertible \( n \times n \) matrices with entries from a field \( F \).
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