will not outperform blind search directly in the ground state space if using a heuristic based on embedding abstractions 
(under certain assumptions on how to compute the heuristic). Holte et al. [61] showed that this result does not transfer to 
homomorphic abstractions, where the total number of explored nodes can be fewer with abstraction. Since homomorphisms 
are  also  well  studied  theoretically  and  have  many  beneﬁcial  properties,  they  have  since  been  the  most  common  type  of 
abstraction function. They are often used in the form of strong (or faithful) homomorphisms. Examples of homomorphic 
abstractions appear, for instance, in the publications by Holte et al. [59], Haslum et al. [45], Helmert et al. [48] and Zilles 
and Holte [92].
A-framework-for-analysing-state-abstraction-metho_2022_Artificial-Intelligen