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CslibFrontier.Computability.Complexity.Problems.PlanarPositiveOneInThreeSAT

Positive exact-one SAT after parsimonious planarization #

The compiler first uses the existing parsimonious planar 3SAT-3 construction and then the constant-factor positive exact-three replacement. The emitted integer orthogonal drawing has the actual output incidence graph. All route contacts concern full real supports.

Relative to a supplied planar drawing, the new replacement changes grid sides and all drawing costs by fixed constants. Relative to the original 3SAT instance, the full composition has linear grid sides and quadratic formula, vertex, route, segment and Manhattan wire costs. Models are counted only on occurring variables, and every ordinary source model has a unique extension.

Main definitions #

Main results #

References #

The local clause gadgets are from [HuntMaratheRadhakrishnanStearns1998, Theorem 3.8]. The quantitative composition is original.

An instance of DrawnPlanarPositiveOneInExactThreeSATThree: a positive CNF formula paired with a finite integer orthogonal drawing of its incidence graph.

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    Binary encoding of a CNF formula and its supplied orthogonal incidence drawing.

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      theorem Cslib.Complexity.encDrawnPlanarPositiveOneInExactThreeSATThree_mk_inO {γ : Type} {encIn : γ ↪ List Bool} {x0 : γ → Logic.PL.CNF ℕ} {T0 S0 : γ → ℕ} {x1 : γ → Graph.OrthogonalDrawing} {T1 S1 : γ → ℕ} (h0 : Turing.MultiTapeTM.ComputableInO x0 encIn encCNF T0 S0) (h1 : Turing.MultiTapeTM.ComputableInO x1 encIn Graph.encOrthogonalDrawing T1 S1) :
      Turing.MultiTapeTM.ComputableInO (fun (x : γ) => { formula := x0 x, drawing := x1 x }) encIn encDrawnPlanarPositiveOneInExactThreeSATThree (fun (x : γ) => T0 x + T1 x) fun (x : γ) => S0 x + S1 x

      Positive exact-three, occurrence-three exact-one formulas with an integer orthogonal incidence drawing whose full real segments meet only at common incident endpoints.

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        The same language with its finite integer incidence drawing supplied as input.

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          The width-at-most-three positive planar variant, without requiring ternary clauses.

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            Count positive exact-three, occurrence-three exact-one models of formulas that have a planar orthogonal incidence drawing; return zero otherwise.

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              Count positive exact-three, occurrence-three exact-one models when the supplied drawing is a planar orthogonal incidence drawing of the formula; return zero otherwise.

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                Apply only the constant-factor positive compiler after the existing planarization.

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                  Compute the actual positive incidence drawing by replacing each planar source clause box.

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                    The local replacements retain the planar compiler's three-occurrence restriction.

                    Counts on occurring variables agree with the original ordinary 3SAT instance.

                    Total correctness of the formula compiler, including ordinary syntax rejection.

                    The new constant-factor replacements retain quadratic growth relative to original 3SAT.

                    Positive exact-three, occurrence-three planar exact-one SAT is NP-hard.

                    Positive width-three, occurrence-three planar exact-one SAT is NP-hard.

                    The planar formula compiler is a native parsimonious reduction to the planarity-guarded count: every output has a planar orthogonal incidence drawing, so the guard never discards a model.

                    The full compiler retains linear grid sides relative to the original ordinary 3SAT input.

                    The actual output formula and drawing all have quadratic size relative to the original ordinary 3SAT input. Segment and wire costs refer to the emitted full routes.

                    Formula labels, vertex coordinates and route coordinates are all computed in native polynomial time under their ordinary binary encodings.

                    Supplying the emitted drawing gives a native parsimonious reduction to the count guarded by the validity of the supplied drawing: the emitted drawing is always a planar orthogonal incidence drawing of the emitted formula.