Homology concordance and an infinite rank subgroup

Two knots are said to be homology concordant if they are smoothly concordant in a homology cobordism. One can define a quotient group using homology concordance similarly to the classical knot concordance group. I will explain how we construct an infinite rank subgroup of the above quotient group. The key ingredient is a computation of applying the filtered mapping cone formula to L-space knots.

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