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Counting Homomorphisms to Cactus Graphs Modulo 2 *

Andreas Göbel, Ann Leslie, David Goldberg, Richerby

unpublished

In this paper, we study *the* *complexity* *of* *counting* *homomorphisms* *modulo* *2*. ...
We show that, for some *cactus* *graphs* H, *counting* *homomorphisms* *to* H *modulo* *2* can be done in polynomial time. ...
Since H 1 is an induced subgraph *of* H, it is a *cactus* *graph*. By Theorems 10 and 13, ⊕HomsToH 1 is ⊕P-hard. By Lemma *2*, ⊕HomsToH is ⊕P-hard. ...

fatcat:arevgojgsbddfpgjd4o73bf4sq