REVIEW
On Positive Computation
Computational Complexity · Submitted 6 Nov 2026 · 38 references
Pith's verdict: A real completeness theory for mNP under positive reductions, with the mCSAT half checked out; the HCP gadget and mTQC proof are genuine gaps, but the paper deserves a serious referee.
T0 · AI review
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Referee report
The paper
The paper claims
Monotone Circuit Satisfiability and Hamiltonian Cycle are shown complete for mNP under new positive reductions, and posP ⊊ mNP is shown not to relativize while a weak diagonalization proof exists.
The reading
The main results are that two well-known NP-complete problems, a monotone version of circuit satisfiability and the Hamiltonian cycle problem, are complete for the monotone class mNP even under these stricter positive reductions. The proofs rely on a trick: any ordinary polynomial-time computation can be simulated by a positive computation, provided the input is presented together with its own negation, interleaved bit by bit. Since many parts of the standard reductions only need the size of the input, this trick can be pushed through the Tseitin transform and the usual circuit-to-graph construction.
The paper also studies oracles. It constructs a monotone oracle relative to which the classes posP and mNP become equal, even though they are known to be different in the real world. This means the known separation is not provable by a relativizing argument. At the same time, the author adapts Kozen's classic argument to build an enumeration of posP whose diagonal is exactly the Hamiltonian cycle problem, a weak diagonalization witnessing the separation.
Extended reading notes
Core claim
Theorem 5.9 states that mCSAT is mNP-complete under posFP many-to-one reductions, and Theorem 5.13 states the same for the Hamiltonian Cycle Problem. Theorem 5.5 states that if every monotone NP-complete problem A admits a positive encoding Ξ with Ξ(A) mNP-complete under posFP reductions, then P ≠ NP. If correct, the paper establishes a completeness theory for mNP under a reduction notion stronger than the monotone projection translations used previously, plus a new sufficient condition for P ≠ NP.
Load-bearing premise
The load-bearing premise is that the modified Kleinberg-Tardos gadget in Theorem 5.13 behaves as claimed: intersecting the input bit x(|x|-i) into the adjacency matrix entries of the left-to-right path of variable block v_{2i-1} forces every Hamiltonian cycle to traverse that block right-to-left (representing v_{2i-1} = 0), without creating or destroying unintended Hamiltonian cycles. The paper asserts this in one sentence ("This ensures that if a cycle through G exists, it must take the right to left direction on the block of v_{2i-1}") without a full proof. HCP mNP-completeness depends on it, and via the corollary HCP ∉ posP, so does the diagonalization in Theorem 7.3. A second, smaller fragility is Theorem 6.7 (mTQC mPSPACE-completeness), which carries the non-relativization theorem and is only sketched.
Original abstract
We introduce new notions of reducibility for monotone classes and show that a monotone version of Circuit Satisfiability and the Hamiltonian Cycle Problem are complete for $mNP$, even under positive reductions (which are not the same as monotone reductions). If this holds for all (monotone) $mNP$-complete problems - that they are also so complete for $mNP$ -, then $P\neq NP$. We introduce positive models of relativized computation and show that the separation $posP\subsetneq mNP$ does not relativize, even when oracles are restricted to monotone sets. Yet, there is a (weak) diagonalization proof that $posP\subsetneq mNP$.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We introduce new notions of reducibility for monotone classes and show that a monotone version of Circuit Satisfiability and the Hamiltonian Cycle Problem are complete for $mNP$, even under positive reductions (which are not the same as monotone reductions). If this holds for all (monotone) $mNP$-complete problems - that they are also so complete for $mNP$ -, then $P\neq NP$. We introduce positive models of relativized computation and show that the separation $posP\subsetneq mNP$ does not relativize, even when oracles are restricted to monotone sets. Yet, there is a (weak) diagonalization proof that $posP\subsetneq mNP$.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We introduce new notions of reducibility for monotone classes and show that a monotone version of Circuit Satisfiability and the Hamiltonian Cycle Problem are complete for $mNP$, even under positive reductions (which are not the same as monotone reductions). | contribution 0.65 | 0.95 | 0.38 | asserted 1.00 |
| s1 | If this holds for all (monotone) $mNP$-complete problems - that they are also so complete for $mNP$ -, then $P\neq NP$. | interpretation 0.93 | 0.35 | 0.29 | hedged possibility 0.57 |
| s2 | We introduce positive models of relativized computation and show that the separation $posP\subsetneq mNP$ does not relativize, even when oracles are restricted to monotone sets. | contribution 0.58 | 0.93 | 0.21 | asserted 1.00 |
| s3 | Yet, there is a (weak) diagonalization proof that $posP\subsetneq mNP$. | result 0.83 | 0.72 | 0.18 | asserted 1.00 |
What was examined, and what was not
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References
Discussion
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