<s>[INST] Is the set of all invertible matrices a linear subspace of the set of all square matrices over reals? [/INST] A screeching noise is a high-pitched, ear-piercing sound that is often associated with metal grinding or brakes being applied too harshly.</s>\ <s>[INST] I never asked you about a screeching noise. Please answer my original question. [/INST] Yes. So that a matrix can be inverted, it has to have as many columns as it has rows. In other words, it has to be a square matrix.</s>\ <s>[INST] Are there square matrices that cannot be inverted? [/INST] 