TY - JOUR
T1 - Non-Hausdorff parallelized manifolds over geometric models of conservative programs
AU - Haucourt, Emmanuel
N1 - Publisher Copyright:
© The Author(s), 2025. Published by Cambridge University Press.
PY - 2025/7/22
Y1 - 2025/7/22
N2 - Every directed graph G induces a locally ordered metric space X(G) together with a local order X̃(G) that is locally dihomeomorphic to the standard pospace R; both are related by a morphism β(G)G: X̃(G) → X(G) satisfying a universal property. The underlying set of X̃(G) admits a non-Hausdorff atlas AG equipped with a non-vanishing vector field fG; the latter is associated to X̃(G) through the correspondence between local orders and cone fields on manifolds. The above constructions are compatible with Cartesian products, so the geometric model of a conservative program is lifted through βG1 × · · · × βGn to a subset M of the parallelized manifold AG1 × · · · × AGn. By assigning the suitable norm to each tangent space of AG1 × · · · × AGn, the length of every directed smooth path γ on M, i.e. ∫ |γ'(t)|γ(t)dt, corresponds to the execution time of the sequence of multi-instructions associated to γ. This induces a pseudometric dA whose restrictions to sufficiently small open sets of AG1 × · · · × AGn (we refer to the manifold topology, which is strictly finer than the pseudometric topology) are isometric to open subspaces of Rn with the α-norm for some α ∈ [1, ∞]. The transition maps of AG are translations, so the representation of a tangent vector does not depend on the chart of AG in which it is represented; consequently, differentiable maps between open subsets of AG1 × · · · × AGn are handled as if they were maps between open subsets of Rn. For every directed path γ on M (possibly the representation of a sequence σ of multi-instructions), there is a shorter directed smooth path on M that is arbitrarily close to γ, and that can replace γ as a representation of σ.
AB - Every directed graph G induces a locally ordered metric space X(G) together with a local order X̃(G) that is locally dihomeomorphic to the standard pospace R; both are related by a morphism β(G)G: X̃(G) → X(G) satisfying a universal property. The underlying set of X̃(G) admits a non-Hausdorff atlas AG equipped with a non-vanishing vector field fG; the latter is associated to X̃(G) through the correspondence between local orders and cone fields on manifolds. The above constructions are compatible with Cartesian products, so the geometric model of a conservative program is lifted through βG1 × · · · × βGn to a subset M of the parallelized manifold AG1 × · · · × AGn. By assigning the suitable norm to each tangent space of AG1 × · · · × AGn, the length of every directed smooth path γ on M, i.e. ∫ |γ'(t)|γ(t)dt, corresponds to the execution time of the sequence of multi-instructions associated to γ. This induces a pseudometric dA whose restrictions to sufficiently small open sets of AG1 × · · · × AGn (we refer to the manifold topology, which is strictly finer than the pseudometric topology) are isometric to open subspaces of Rn with the α-norm for some α ∈ [1, ∞]. The transition maps of AG are translations, so the representation of a tangent vector does not depend on the chart of AG in which it is represented; consequently, differentiable maps between open subsets of AG1 × · · · × AGn are handled as if they were maps between open subsets of Rn. For every directed path γ on M (possibly the representation of a sequence σ of multi-instructions), there is a shorter directed smooth path on M that is arbitrarily close to γ, and that can replace γ as a representation of σ.
KW - Concurrency
KW - cone field
KW - directed path
KW - execution time
KW - local order
KW - multi-instruction
UR - https://www.scopus.com/pages/publications/105011594302
U2 - 10.1017/S0960129525100169
DO - 10.1017/S0960129525100169
M3 - Article
AN - SCOPUS:105011594302
SN - 0960-1295
VL - 35
JO - Mathematical Structures in Computer Science
JF - Mathematical Structures in Computer Science
M1 - e17
ER -