Rigor and Strang are not two words I'd put in the same sentence. Neil Strickland's notes https://neilstrickland.github.io/linear_maths/ https://neilstrickland.g

Rigor and Strang are not two words I'd put in the same sentence. Neil Strickland's notes https://neilstrickland.github.io/linear_maths/ https://neilstrickland.github.io/linear_maths/ (for the matrix point of view) or Jim Hefferon's book https://joshua.smcvt.edu/linearalgebra/index.html https://joshua.smcvt.edu/linearalgebra/index.html (for a vector-spacey treatment) are what comes to my mind when I think "rigor" (along with all sorts of older textbooks like Hoffman/Kunze); Jean Gallier's long set of notes https://www.cis.upenn.edu/~jean/math-deep.pdf https://www.cis.upenn.edu/~jean/math-deep.pdf goes even further in that direction.