The nonzero determinant shows this joint table cannot be split into two hidden single-particle answer lists. That check is exact only for the stated amplitude table; real Bell-style evidence depends on measurement settings, selection assumptions, detector efficiency, noise, and statistical confidence.
The entanglement claim is checked by a nonzero determinant, not a caption. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A product check uses a determinant
For a two-by-two amplitude table, a product state would have determinant 0.
productdet=0
The determinant scan separates product from Bell state
A product table would have zero determinant; this checked table does not.