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STEPHAN KREUTZER COMPLEXITY OF MODEL-CHECKING PROBLEMS 45/81<br />

INTRODUCTION COMPLEXITY UPPER BOUNDS COMPOSITION LOCALITY LOCALISATION GRIDS GRID-LIKE MINORS LABELLED WEBS<br />

Localisation of Graph Invariants<br />

Definition:<br />

Let f : GRAPHS → N be a graph invariant.<br />

We define its localisation loc f : GRAPHS×N → N as<br />

{ (<br />

loc f (G, r) := max f G [ N r (v) ]) }<br />

: v ∈ V(G) .<br />

A class C of graphs has bounded local f , if there is a computable function<br />

h : N → N such that loc f (G, r) ≤ h(r) for all G ∈ C and r ∈ N.<br />

Example: f : G ↦→ tw(G) tree-width of graphs<br />

{ (<br />

loc f (G, r) := max tw G [ N r (v) ]) }<br />

: v ∈ V(G)<br />

Bounded local tree-width

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