“…Obstructions to a knot or link being ‐solvable are obstructions to the knot or link bounding a grope of height , so the preceding proposition translates many results from the literature on the solvable filtration into statements about the distance between knots in our grope metric. For the convenience of the reader we recall the definition of ‐solvability for knots, originating from , and reformulated as given below in [, Definition 2.3]. Definition We say that a knot is ‐solvable if the zero surgery manifold bounds a compact oriented 4‐manifold with the inclusion induced map an isomorphism for , and such that has a basis consisting of embedded, connected, compact, oriented surfaces with trivial normal bundles satisfying: - (i) and for all ;
- (ii)the geometric intersection numbers are
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