A note on the weak splitting number

The weak splitting number wsp(L) of a link L is the minimal number of crossing changes needed to turn into a split union of knots. We describe conditions under which certain real-valued link invariants give lower bounds on . This result is used both to obtain new bounds on in terms of the multivariable signature and to recover known lower bounds in terms of the \tau and s-invariants. We also establish new obstructions using link Floer homology and apply all these methods to compute wsp for all but two of the 130 prime links with nine or fewer crossings.