We describe equivariant SL.2/ and SL.3/ homology for links in the thickened annulus via foam evaluation. The thickened annulus is replaced by 3-space with a distinguished line in it. Generators of state spaces for annular webs are represented by foams with boundary that may intersect the distinguished line; intersection points, called anchor points, contribute additional terms, reminiscent of square roots of the Hessian, to the foam evaluation. Both oriented and unoriented SL.3/ foams are treated.
57K18; 18N25, 57K16 1 IntroductionAsaeda-Przytycki-Sikora [2] homology of links in the thickened annulus has led to a number of interesting developments -see the first author [1], Baldwin, Beliakova, Grigsby, Licata, Putyra and Wehrli [3;5;11;12;13] and Roberts [35] -and extensions of their work to SL.N / and GL.N / link homology in the thickened annulus -see Queffelec, Rose, Sartori and Wedrich [30;31;32]. GL.N / and SL.N / link homology theories are closely related to foam evaluation. This connection was made the most transparent by the work of Robert and Wagner [34], who wrote down a combinatorial formula for GL.N / closed foam evaluation that allows to build GL.N / link homology from the ground up, bypassing categorical approaches to the latter. A variation of their formula was used by Robert and the second author [18] to evaluate unoriented SL.3/ foams, giving a combinatorial approach to some of the structures discovered by Kronheimer and Mrowka [23].In this paper we extend foam evaluation framework to build equivariant SL.2/ and SL.3/ state spaces for annular webs and, consequently, equivariant SL.2/ and SL.3/ homology for links in the thickened annulus. Our construction complements earlier work [30; 32] on the subject. The same approach allows us to define state spaces for