determinant polynomial (a,b,c,d exponents; coefficient): [((0, 1, 1, 2), '1'), ((1, 0, 0, 3), '-1')]
PASS exact polynomial identity det(B)=-d^2*(ad-bc); on SL2, det(B)=-d^2
PASS both maps are Lie homomorphisms on all basis pairs
source_trace_ad_H=2; source is nonunimodular
PASS f(identity)=-1 but f(Weyl)=0 for actual SL2 points
VERIFIED DROPPED-HYPOTHESIS EXAMPLE: initial transversality need not be global without unimodularity
This checks the mechanism; it is not a counterexample under the target hypotheses.
