optional · interactive figures
06
Explore: total unimodularity
Pick submatrices and see their determinants, sign rows until the columns behave, and watch the odd cycle break both.
optional: nothing in the lab depends on itback to the slides
06 · explore
Determinants, one submatrix at a time
Try: on the triangle, pick all three rows and columns; then press "check every square submatrix" on each matrix. Static version: TU, checked by hand.
06 · explore
Ghouila-Houri signings, by hand
Try: on the triangle, sign all three rows and search for a good signing; then "test every row subset". Static version: a signing, worked.