Knowledge graph embedding (KGE) is a increasingly popular technique that aims to represent entities and relations of knowledge graphs into low-dimensional semantic spaces for a wide spectrum of applications such as link prediction, knowledge reasoning and knowledge completion. In this paper, we provide a systematic review of existing KGE techniques based on representation spaces. Particularly, we build a fine-grained classification to categorise the models based on three mathematical perspectives of the representation spaces: (1) Algebraic perspective, (2) Geometric perspective, and (3) Analytical perspective. We introduce the rigorous definitions of fundamental mathematical spaces before diving into KGE models and their mathematical properties. We further discuss different KGE methods over the three categories, as well as summarise how spatial advantages work over different embedding needs. By collating the experimental results from downstream tasks, we also explore the advantages of mathematical space in different scenarios and the reasons behind them. We further state some promising research directions from a representation space perspective, with which we hope to inspire researchers to design their KGE models as well as their related applications with more consideration of their mathematical space properties.

知识图（kg）嵌入在实体的学习表示和链接预测任务的关系方面表现出很大的力量。以前的工作通常将KG嵌入到单个几何空间中，例如欧几里得空间（零弯曲），双曲空间（负弯曲）或超透明空间（积极弯曲），以维持其特定的几何结构（例如，链，层次结构和环形结构）。但是，KGS的拓扑结构似乎很复杂，因为它可能同时包含多种类型的几何结构。因此，将kg嵌入单个空间中，无论欧几里得空间，双曲线空间或透明空间，都无法准确捕获KGS的复杂结构。为了克服这一挑战，我们提出了几何相互作用知识图嵌入（GIE），该图形嵌入了，该图形在欧几里得，双曲线和超级空间之间进行了交互学习的空间结构。从理论上讲，我们提出的GIE可以捕获一组更丰富的关系信息，模型键推理模式，并启用跨实体的表达语义匹配。三个完善的知识图完成基准的实验结果表明，我们的GIE以更少的参数实现了最先进的性能。

Knowledge graph (KG) embedding is to embed components of a KG including entities and relations into continuous vector spaces, so as to simplify the manipulation while preserving the inherent structure of the KG. It can benefit a variety of downstream tasks such as KG completion and relation extraction, and hence has quickly gained massive attention. In this article, we provide a systematic review of existing techniques, including not only the state-of-the-arts but also those with latest trends. Particularly, we make the review based on the type of information used in the embedding task. Techniques that conduct embedding using only facts observed in the KG are first introduced. We describe the overall framework, specific model design, typical training procedures, as well as pros and cons of such techniques. After that, we discuss techniques that further incorporate additional information besides facts. We focus specifically on the use of entity types, relation paths, textual descriptions, and logical rules. Finally, we briefly introduce how KG embedding can be applied to and benefit a wide variety of downstream tasks such as KG completion, relation extraction, question answering, and so forth.

两视图知识图（kgs）共同表示两个组成部分：抽象和常识概念的本体论观点，以及针对本体论概念实例化的特定实体的实例视图。因此，这些kg包含来自实例视图的本体学和周期性的分层的异质结构。尽管KG中有这些不同的结构，但最新的嵌入KG的作品假设整个KG仅属于两个观点之一，但并非同时属于。对于寻求将KG视为两种视图的作品，假定实例和本体论的观点属于相同的几何空间，例如所有嵌入在同一欧几里得空间中的节点或非欧盟产品空间，不再是合理的。对于两视图kg，图表的不同部分显示出不同的结构。为了解决这个问题，我们定义并构建了一个双几何空间嵌入模型（DGS），该模型通过将KG的不同部分嵌入不同的几何空间中，该模型使用复杂的非欧盟几何几何空间进行对两视图KGS进行建模。 DGS利用球形空间，双曲线空间及其在统一框架中学习嵌入的框架中的相交空间。此外，对于球形空间，我们提出了直接在球形空间中运行的新型封闭的球形空间操作员，而无需映射到近似切线空间。公共数据集上的实验表明，DGS在KG完成任务上的先前最先进的基线模型明显优于先前的基线模型，这表明了其在KGS中更好地建模异质结构的能力。

捕获关系的构图模式是知识图表完成中的重要任务。它还是迈向多跳推理的基本步骤，以了解学到的知识。以前，已经开发了几种基于旋转的翻译方法来使用一系列复值对角线矩阵的产品来模拟复合关系。然而，这些方法倾向于对复合关系进行几种超薄假设，例如，强迫他们独立于实体和缺乏语义等级的交换。为了系统地解决这些问题，我们开发了一种新颖的知识图形嵌入方法，命名为密集，为复杂的关系模式提供改进的建模方案。特别地，我们的方法将每个关系分解成SO（3）基于基于组的旋转操作员和三维（3-D）欧几里德空间中的缩放操作员。这种设计原理导致我们的方法的几个优点：（1）对于复合关系，相应的对角线关系矩阵可以是非换向的，反映了现实世界应用中的主要情景; （2）我们的模型保留了关系运营和实体嵌入之间的自然互动; （3）缩放操作为实体的内在语义层次结构提供建模电力; （4）在参数大小和培训时间方面，以高计算效率实现致密的增强效果; （5）欧几里德空间中的建模实体而不是四元数空间，保持关系模式的直接几何解释。多个基准知识图上的实验结果表明，密集优于当前最先进的模型，以缺少链路预测，尤其是对复合关系。

事实证明，信息提取方法可有效从结构化或非结构化数据中提取三重。以（头部实体，关系，尾部实体）形式组织这样的三元组的组织称为知识图（kgs）。当前的大多数知识图都是不完整的。为了在下游任务中使用kgs，希望预测kgs中缺少链接。最近，通过将实体和关系嵌入到低维的矢量空间中，旨在根据先前访问的三元组来预测三元组，从而对KGS表示不同的方法。根据如何独立或依赖对三元组进行处理，我们将知识图完成的任务分为传统和图形神经网络表示学习，并更详细地讨论它们。在传统的方法中，每个三重三倍将独立处理，并在基于GNN的方法中进行处理，三倍也考虑了他们的当地社区。查看全文

The choice of geometric space for knowledge graph (KG) embeddings can have significant effects on the performance of KG completion tasks. The hyperbolic geometry has been shown to capture the hierarchical patterns due to its tree-like metrics, which addressed the limitations of the Euclidean embedding models. Recent explorations of the complex hyperbolic geometry further improved the hyperbolic embeddings for capturing a variety of hierarchical structures. However, the performance of the hyperbolic KG embedding models for non-transitive relations is still unpromising, while the complex hyperbolic embeddings do not deal with multi-relations. This paper aims to utilize the representation capacity of the complex hyperbolic geometry in multi-relational KG embeddings. To apply the geometric transformations which account for different relations and the attention mechanism in the complex hyperbolic space, we propose to use the fast Fourier transform (FFT) as the conversion between the real and complex hyperbolic space. Constructing the attention-based transformations in the complex space is very challenging, while the proposed Fourier transform-based complex hyperbolic approaches provide a simple and effective solution. Experimental results show that our methods outperform the baselines, including the Euclidean and the real hyperbolic embedding models.

We study the problem of learning representations of entities and relations in knowledge graphs for predicting missing links. The success of such a task heavily relies on the ability of modeling and inferring the patterns of (or between) the relations. In this paper, we present a new approach for knowledge graph embedding called RotatE, which is able to model and infer various relation patterns including: symmetry/antisymmetry, inversion, and composition. Specifically, the RotatE model defines each relation as a rotation from the source entity to the target entity in the complex vector space. In addition, we propose a novel self-adversarial negative sampling technique for efficiently and effectively training the RotatE model. Experimental results on multiple benchmark knowledge graphs show that the proposed RotatE model is not only scalable, but also able to infer and model various relation patterns and significantly outperform existing state-of-the-art models for link prediction.

最近公布的知识图形嵌入模型的实施，培训和评估的异质性已经公平和彻底的比较困难。为了评估先前公布的结果的再现性，我们在Pykeen软件包中重新实施和评估了21个交互模型。在这里，我们概述了哪些结果可以通过其报告的超参数再现，这只能以备用的超参数再现，并且无法再现，并且可以提供洞察力，以及为什么会有这种情况。然后，我们在四个数据集上进行了大规模的基准测试，其中数千个实验和24,804 GPU的计算时间。我们展示了最佳实践，每个模型的最佳配置以及可以通过先前发布的最佳配置进行改进的洞察。我们的结果强调了模型架构，训练方法，丢失功能和逆关系显式建模的组合对于模型的性能来说至关重要，而不仅由模型架构决定。我们提供了证据表明，在仔细配置时，若干架构可以获得对最先进的结果。我们制定了所有代码，实验配置，结果和分析，导致我们在https://github.com/pykeen/pykeen和https://github.com/pykeen/benchmarking中获得的解释

翻译，旋转和缩放是图像处理中三个常用的几何操作操作。此外，其中一些成功用于开发有效的知识图嵌入（KGE）模型，例如transe和旋转。受协同作用的启发，我们通过利用这项工作中的所有三项操作提出了一个新的KGE模型。由于翻译，旋转和缩放操作被级联形成一个复合的操作，因此新模型被命名为复合。通过在小组理论的框架中铸造复合物，我们表明，基于得分功能的KGE模型是复合的特殊情况。Compounde将简单的基于距离的关系扩展到与关系有关的化合物操作上的头部和/或尾部实体。为了证明化合物的有效性，我们对三个流行的KG完成数据集进行了实验。实验结果表明，复合者始终达到了现状的性能。

知识图嵌入（KGE）的有效性在很大程度上取决于建模固有关系模式和映射属性的能力。但是，现有方法只能以不足的建模能力捕获其中的一些。在这项工作中，我们提出了一个名为House的更强大的KGE框架，该框架涉及基于两种家庭转换的新型参数化：（1）住户旋转以实现建模关系模式的较高能力；（2）处理复杂关系映射属性的住户预测。从理论上讲，房屋能够同时建模关键的关系模式和映射属性。此外，房屋是对现有基于旋转的模型的概括，同时将旋转扩展到高维空间。从经验上讲，House在五个基准数据集上实现了新的最新性能。我们的代码可在https://github.com/anrep/house上找到。

Knowledge graph reasoning (KGR), aiming to deduce new facts from existing facts based on mined logic rules underlying knowledge graphs (KGs), has become a fast-growing research direction. It has been proven to significantly benefit the usage of KGs in many AI applications, such as question answering and recommendation systems, etc. According to the graph types, the existing KGR models can be roughly divided into three categories, \textit{i.e.,} static models, temporal models, and multi-modal models. The early works in this domain mainly focus on static KGR and tend to directly apply general knowledge graph embedding models to the reasoning task. However, these models are not suitable for more complex but practical tasks, such as inductive static KGR, temporal KGR, and multi-modal KGR. To this end, multiple works have been developed recently, but no survey papers and open-source repositories comprehensively summarize and discuss models in this important direction. To fill the gap, we conduct a survey for knowledge graph reasoning tracing from static to temporal and then to multi-modal KGs. Concretely, the preliminaries, summaries of KGR models, and typical datasets are introduced and discussed consequently. Moreover, we discuss the challenges and potential opportunities. The corresponding open-source repository is shared on GitHub: https://github.com/LIANGKE23/Awesome-Knowledge-Graph-Reasoning.

知识图（kgs）在许多应用程序中越来越重要的基础架构，同时患有不完整问题。 KG完成任务（KGC）自动根据不完整的KG预测缺失的事实。但是，现有方法在现实情况下表现不佳。一方面，他们的性能将巨大的降解，而kg的稀疏性越来越大。另一方面，预测的推理过程是一个不可信的黑匣子。本文提出了一个稀疏kgc的新型可解释模型，将高阶推理组合到图形卷积网络中，即HOGRN。它不仅可以提高减轻信息不足问题的概括能力，而且还可以在保持模型的有效性和效率的同时提供可解释性。有两个主要组件无缝集成以进行关节优化。首先，高阶推理成分通过捕获关系之间的内源性相关性来学习高质量的关系表示。这可以反映逻辑规则，以证明更广泛的事实是合理的。其次，更新组件的实体利用无重量的图形卷积网络（GCN）有效地模拟具有可解释性的KG结构。与常规方法不同，我们在没有其他参数的情况下在关系空间中进行实体聚合和基于设计组成的注意。轻巧的设计使HOGRN更适合稀疏设置。为了进行评估，我们进行了广泛的实验 - HOGRN对几个稀疏KG的结果表现出了令人印象深刻的改善（平均为9％的MRR增益）。进一步的消融和案例研究证明了主要成分的有效性。我们的代码将在接受后发布。

知识图，例如Wikidata，包括结构和文本知识，以表示知识。对于图形嵌入和语言模型的两种方式中的每种方法都可以学习预测新型结构知识的模式。很少有方法与模式结合学习和推断，而这些现有的方法只能部分利用结构和文本知识的相互作用。在我们的方法中，我们以单个方式的现有强烈表示为基础，并使用超复杂代数来表示（i），（i），单模式嵌入以及（ii），不同方式之间的相互作用及其互补的知识表示手段。更具体地说，我们建议4D超复合数的二脑和四个元素表示，以整合四个模态，即结构知识图形嵌入，单词级表示（例如\ word2vec，fastText，fastText），句子级表示（句子transformer）和文档级表示（句子级别）（句子级别）（句子级表示）（句子变压器，doc2vec）。我们的统一矢量表示通过汉密尔顿和二脑产物进行标记的边缘的合理性，从而对不同模态之间的成对相互作用进行建模。对标准基准数据集的广泛实验评估显示了我们两个新模型的优越性，除了稀疏的结构知识外，还可以提高链接预测任务中的性能。

Covid-19上的知识图（KGS）已建立在加速Covid-19的研究过程中。然而，KGs总是不完整，特别是新建造的Covid-19公斤。链路预测任务旨在预测（e，r，t）或（h，r，e）的丢失实体，其中H和t是某些实体，E是需要预测的实体，R是关系。这项任务还有可能解决Covid-19相关的KGS的不完全问题。虽然已经提出了各种知识图形嵌入（KGE）方法的链路预测任务，但这些现有方法遭受了使用单个评分函数的限制，这不能捕获Covid-19 Kgs的丰富特征。在这项工作中，我们提出了利用多个评分函数来提取来自现有三元组的更多特征的MDistmult模型。我们在CCKS2020 Covid-19抗病毒药物知识图（CADKG）上采用实验。实验结果表明，我们的MDistmult在CADKG数据集上的链路预测任务中实现了最先进的性能

Knowledge graph embedding (KGE), which maps entities and relations in a knowledge graph into continuous vector spaces, has achieved great success in predicting missing links in knowledge graphs. However, knowledge graphs often contain incomplete triples that are difficult to inductively infer by KGEs. To address this challenge, we resort to analogical inference and propose a novel and general self-supervised framework AnKGE to enhance KGE models with analogical inference capability. We propose an analogical object retriever that retrieves appropriate analogical objects from entity-level, relation-level, and triple-level. And in AnKGE, we train an analogy function for each level of analogical inference with the original element embedding from a well-trained KGE model as input, which outputs the analogical object embedding. In order to combine inductive inference capability from the original KGE model and analogical inference capability enhanced by AnKGE, we interpolate the analogy score with the base model score and introduce the adaptive weights in the score function for prediction. Through extensive experiments on FB15k-237 and WN18RR datasets, we show that AnKGE achieves competitive results on link prediction task and well performs analogical inference.

Graph is an important data representation which appears in a wide diversity of real-world scenarios. Effective graph analytics provides users a deeper understanding of what is behind the data, and thus can benefit a lot of useful applications such as node classification, node recommendation, link prediction, etc. However, most graph analytics methods suffer the high computation and space cost. Graph embedding is an effective yet efficient way to solve the graph analytics problem. It converts the graph data into a low dimensional space in which the graph structural information and graph properties are maximumly preserved. In this survey, we conduct a comprehensive review of the literature in graph embedding. We first introduce the formal definition of graph embedding as well as the related concepts. After that, we propose two taxonomies of graph embedding which correspond to what challenges exist in different graph embedding problem settings and how the existing work address these challenges in their solutions. Finally, we summarize the applications that graph embedding enables and suggest four promising future research directions in terms of computation efficiency, problem settings, techniques and application scenarios.

Knowledge graphs (KG) have served as the key component of various natural language processing applications. Commonsense knowledge graphs (CKG) are a special type of KG, where entities and relations are composed of free-form text. However, previous works in KG completion and CKG completion suffer from long-tail relations and newly-added relations which do not have many know triples for training. In light of this, few-shot KG completion (FKGC), which requires the strengths of graph representation learning and few-shot learning, has been proposed to challenge the problem of limited annotated data. In this paper, we comprehensively survey previous attempts on such tasks in the form of a series of methods and applications. Specifically, we first introduce FKGC challenges, commonly used KGs, and CKGs. Then we systematically categorize and summarize existing works in terms of the type of KGs and the methods. Finally, we present applications of FKGC models on prediction tasks in different areas and share our thoughts on future research directions of FKGC.

知识图本质上是不完整的。因此，大量研究是针对知识图完成（KGC）的，即，从知识图（KG）中表示的信息中预测了丢失的三元组。嵌入模型已经为KGC产生了有希望的结果，但是当前的KGC嵌入模型都无法：（1）完全捕获重要的推理模式（例如组成），（2）共同捕获突出的逻辑规则（例如，层次结构和组成），以及（3）提供捕获模式的直观解释。在这项工作中，我们提出了表达式，这是一种完全表达的空间功能嵌入模型，可以同时解决所有这些挑战。表达式将成对的实体作为点和关系作为虚拟三重空间$ \ mathbb {r}^{2d} $中的超平行平行四边形。该模型设计不仅可以共同捕获一组丰富的推理模式，而且还可以通过超平行平行四边形的空间关系来显示任何受支持的推理模式，从而提供表达嵌入及其捕获模式的直观且一致的几何解释。标准KGC基准测试的实验结果表明，表达性与最先进的模型具有竞争力，甚至在WN18RR上的表现明显优于它们。

知识图嵌入（KGE）旨在将实体和关系映射到低维空间，并成为知识图完成的\ textit {de-facto}标准。大多数现有的KGE方法都受到稀疏挑战的困扰，在这种挑战中，很难预测在知识图中频繁的实体。在这项工作中，我们提出了一个新颖的框架KRACL，以减轻具有图表和对比度学习的KG中广泛的稀疏性。首先，我们建议知识关系网络（KRAT）通过同时将相邻的三元组投射到不同的潜在空间，并通过注意机制共同汇总信息来利用图形上下文。 KRAT能够捕获不同上下文三联的微妙的语义信息和重要性，并利用知识图中的多跳信息。其次，我们通过将对比度损失与跨熵损失相结合，提出知识对比损失，这引入了更多的负样本，从而丰富了对稀疏实体的反馈。我们的实验表明，KRACL在各种标准知识基准中取得了卓越的结果，尤其是在WN18RR和NELL-995上，具有大量低级内实体。广泛的实验还具有KRACL在处理稀疏知识图和鲁棒性三元组的鲁棒性方面的有效性。