Strong permanent inequalities for complex books and orthogonal three-center extensions
Authors/Creators
Description
We prove that the permanent of the entrywise squared-modulus matrix is at most the permanent of a
complex positive semidefinite correlation matrix whose support is contained in a book graph, that
is, per(A ∘ Ā) ≤ per(A) for such A. This strong inequality is the self-conjugate case of a question
of Bapat and Sunder; it fails for general positive semidefinite matrices by a counterexample of
Drury, so structural hypotheses are essential. The number of leaves is arbitrary, and no rank or
phase restriction is imposed. We determine all equality cases and obtain the corresponding
inequality for one-point assemblies of book blocks. We also treat matrices with three centers and
pairwise orthogonal leaf rows. Every feasible path on the centers satisfies the same strong
inequality; a full center triangle is allowed under explicit row-energy and cyclic-product
conditions. The proofs retain exact occupation contributions, use squared Gram norms to quantify
slack, and reduce the two-center phase dependence to homogeneous quartic certificates. For three
centers, a weighted deletion inequality and Schur-complement estimates control the phase terms
without allocating the same slack more than once. The conclusions concern the stated structured
classes and do not resolve the unrestricted Chollet conjecture.
Verification programs are attached: Verification_Supplement.zip contains exact-arithmetic checkers
for every displayed certificate and identity (Python standard library) and a second, independently
written set of programs (exact and 50-digit permanents, symbolic re-derivation of the certificates,
adversarial searches), with logs and a README.