This paper describes several cases of adjunction in the homomorphism order of relational structures. For these purposes, we say that two functors $\Gamma$ and $\Delta$ between categories of relational structures are adjoint if for all structures $A$ and $B$, we have that $\Gamma(A)$ maps homomorphically to $B$ if and only if $A$ maps homomorphically to $\Delta(B)$. If this is the case $\Gamma$ is called the left adjoint to $\Delta$ and $\Delta$ the right adjoint to $\Gamma$. In 2015, Foniok and Tardif described some functors category of digraphs that allow both left and right adjoints. The main contribution of Foniok and Tardif is a construction of right adjoints to some of the functors identified as right adjoints by Pultr in 1970. We generalise results of Foniok and Tardif to arbitrary relational relational structures, and coincidentely, we also provide more right adjoints on digraphs, and since these constructions are connected to finite duality, we also provide a new construction of duals to trees. Our results are motivated by the application in promise constraint satisfaction -- it has been shown that such functors can be used as efficient reductions between these problems.

翻译：本文描述了关系结构同质顺序中的几例附加案例。 为此,我们说,如果在所有结构中,美元和美元都是A美元,那么,如果在所有结构中,美元和美元是B美元,那么,美元(A)的地图与美元相同,如果而且只有美元(A)的地图与美元(B)的相同,美元(A)的地图与美元(B)的相同,则美元(B)的相同。如果是这种情况,美元(Gamma)被称为左接合美元(Delta$)和美元(Delta$),则在关系结构类别中,美元和美元(Delta$)的右接合。2015年,Foniok和Tardif描述了一些允许左接和右接合的真菌类别。 Foniok和Tardif的主要贡献是,与Pultrtr(Pultr)确定为右接合体的一些真菌(Foniok和Tardif)的正确连接。我们把Foniok和Tardif的结果概括到任意关系结构中的右接合起来, 也同时显示了我们两联性结构的满意度的两维度的对比性结果。</s>