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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>International Conference on Computer and Intelligent Control, June</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Exploring the potential of language models for graph learning: opportunities and challenges</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Yuqun Wang</string-name>
          <email>wangyuqun18@nudt.edu.cn</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Libin Chen</string-name>
          <email>chenlibin@nudt.edu.cn</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Qian Li</string-name>
          <email>liqian.nudt@nudt.edu.cn</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Hongfu Liu</string-name>
          <email>liuhongfu@nudt.edu.cn</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="editor">
          <string-name>Large Language Models, Graph Neural Networks, Natural Language Processing, Graph Learning</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>College of Intelligence Science and Technology, National University of Defense Technology</institution>
          ,
          <addr-line>Changsha</addr-line>
          ,
          <country country="CN">China</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2024</year>
      </pub-date>
      <volume>2</volume>
      <fpage>9</fpage>
      <lpage>30</lpage>
      <abstract>
        <p>Graph learning methods are becoming increasingly popular in solving problems related to social networks, biological networks, and other real-world applications. With the rapid development of large language models (LLMs), they are also being used for graph-related tasks and combined with traditional graph neural network (GNN)-based approaches to improve the ability to process graphs associated with text and graph-structured data. In this paper, we provide a review and analyse existing approaches. Firstly, we propose a new taxonomy that classifies existing methods into three categories based on LLMs and GNNs who serve as the final task solving component. Based on this, representative models among them are summarised for each category. Finally, we analyse the limitations of the existing methods and provide an outlook on future research directions in this area.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>Graph data, found in diverse forms such as the Internet, traffic networks, social networks,
and biological networks, can be effectively represented through graphs. The analysis and
mining of this data have become pivotal areas of research. Graph neural networks based
on deep learning graph modeling methods have become a new field developed in recent
years based on traditional neural networks. These networks are able to better overcome
the limitations imposed by traditional deep neural network learning by defining suitable
neural network models on graph data and applying the deep learning approach to graph
data.</p>
      <p>However, in the real world, more and more nodes or connecting edges of graphs are
associated with attributes in the form of text. Yet some existing graph neural network
methods still have some limitations in dealing with textual attributes of nodes in graph
data. Traditional graph neural network methods mainly model the inputs or outputs
consisting of nodes and edges on a graph, but ignore the textual attributes contained in the
nodes themselves and are unable to model the original textual information.</p>
      <p>The advent of Large Language Models (LLMs) has brought new perspectives to this
challenge. Large-scale language models, capable of harnessing vast amounts of data, offer
strong language understanding and generalization capabilities. As a deep learning-based
natural language processing model, LLMs are trained on extensive corpora, enabling them
to handle a variety of linguistic tasks. The launch of GPT-3 in 2020 garnered significant
attention from scholars towards LLMs, sparking the question: Can Large Language Models
leverage their potential in graph learning to overcome the limitations of traditional graph
neural network approaches? Although this question has been studied and explored by
scholars, systematic research reviews examining the impact of large language models on
graph learning remain sparse.</p>
      <p>
        Liu et al. [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], inspired by the foundational roles of LLMs in natural language processing
and GNNs in graph data processing, proposed the concept of 'graph foundation models'
and provided a definition. Li et al. [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] investigated the advancements and potential future
directions of large language models in graph-related tasks. This article aims to explore and
summarize the rapidly evolving field, offering an overview of the influence of language
models on graph learning for those interested in pursuing research in this area.
      </p>
      <p>Contributions. The main contributions of this paper are summarised as follows.(1) We
present the findings of research in the field through a structured taxonomy, which
categorizes the existing studies into three distinct classes. (2) Systematic methodological
review. For different classification methods, we summarise representative models,
describe each model in more detail, and summarise their strengths and weaknesses as
well as limitations. (3) Future directions. We provide an in-depth discussion of the
limitations of the current work and suggest possible directions for future development in
the field.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Preliminarys</title>
      <p>In this section, we introduce the definition of a correlation graph and formalise the
concepts and definitions related to the two key areas of large language models and graph
neural networks and their development.</p>
      <sec id="sec-2-1">
        <title>2.1 Definition</title>
        <p> Definition 1(Graph).</p>
        <p>A graph is a collection of nodes and edges. A graph is denoted by  = ( ,  ), where is the
set of nodes and is the set of edges. In an undirected graph, edges can be viewed as
unordered pairs connecting two nodes; in a directed graph, edges can be viewed as
ordered pairs connecting a start node and an end node.</p>
        <p> Definition 2(Text Attribute Graph (TAG)).</p>
        <p>For a textual attribute graph, each node is associated with a contiguous textual feature
(sentence). the form of the TAG can be represented as  = ( ,  ,  ), where each   ∈  is
associated with some textual information    ∈  .</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2 Graph Neural Networks</title>
        <p>Graph Neural Networks are neural network architectures designed to solve tasks related
on graph-structured data. The basic idea is to iteratively update the representation of a
node by combining the representations of its neighbours and the node's own
representation. Graph data is modelled and inferred by learning the interactions between
nodes and the global structure of the graph.GNNs perform well in many graph related
tasks such as node classification, link prediction and graph generation.</p>
        <p>A typical graph neural network consists of multiple graph neural network layers, each
of which consists of two main steps: information aggregation and feature update. Below is
a simplified formulation of a graph neural network layer.</p>
        <p>Information Aggregation Aggregation:
ℎ

( )
=       ( )
ℎ

( − ), ∀ ∈ Ne( ) denotes the hidden state of the node at
layer i.       ( ) is an aggregation function that aggregates the hidden states ℎ
of the neighbours of node i, node j. Ne( ) denotes the set of neighbouring nodes connected
( − )
to node i.</p>
        <p>Feature Update (Update):
ℎ(1) =  
i
 (1) ℎ(1−1)
i</p>
        <p>, ℎi(1) is an update function that combines the hidden state
ℎ(1−1) of the previous layer of node i and the hidden state ℎi(1) of the current layer,to
i
generate a new node representation.</p>
        <p>By stacking multiple graph neural network layers, information can be propagated layer
by layer from neighbouring nodes and capture relationships between nodes further away.
Eventually, the graph neural network produces a final representation of each node that
can be used for different graph-related tasks.</p>
        <p>
          It is important to note that the above formulation is just a simple example, and there
are many variants and improvements of graph neural network models in practice, such as
GraphSAGE [
          <xref ref-type="bibr" rid="ref21">21</xref>
          ], GCN [
          <xref ref-type="bibr" rid="ref22">22</xref>
          ], GAT [
          <xref ref-type="bibr" rid="ref23">23</xref>
          ], etc., which may use different aggregation and
updating functions, as well as other techniques to process graph data
        </p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3 Large Language Models</title>
        <p>In recent years, researchers have paid more and more attention to the evolution and
development of language models, by expanding the amount of pre-trained language
models and the amount of data, Large language model can not only improve the effect of
task processing, and can show many special capabilities that small models do not have.</p>
        <p>
          The underlying layer of large language model basically adopts the Transformer
structure. Currently, the common large language models are BERT [
          <xref ref-type="bibr" rid="ref19">19</xref>
          ], GPT [
          <xref ref-type="bibr" rid="ref20">20</xref>
          ]. BERT
model adopts the bi-directional encoding layer in the 12-layer Transformer structure to
represent the network, but it only adopts the encoding layer of the Transformer as the
theme framework, which makes it more difficult to solve the tasks of text generation such
as article continuation, translation, etc. GPT adopts the decoding layer of the Transformer
as the theme framework, which makes it more difficult to solve the tasks of text generation
such as article continuation and translation. GPT adopts the decoding layer of Transformer
as the main structure of the network for modelling, so it is very effective in text generation
tasks, compared with the BERT model, GPT does not care much about the understanding
of the current language representation, and focuses on how to continue to generate the
rest of the text.
        </p>
        <p>Large language models also include other components and techniques such as
positional coding, multilayer stacking, pre-training and fine-tuning. By pre-training on
large-scale textual data, these models can learn rich linguistic knowledge and show strong
performance capabilities in various natural language processing tasks.</p>
      </sec>
      <sec id="sec-2-4">
        <title>2.4 Proposed Taxonomy</title>
        <p>Depending on the final solution component for solving graph-related problems, we classify
the combined LLM and GNN approach into three categories:(1) GNN as the final
component for task solving. In this case, LLM functions as a text encoder, processing the
input textual information to aid the GNN in task-solving. (2) LLM as the final component of
task solving. In this category. In this type, there are two scenarios; one involves using
GNNs to encode graph structures, thereby assisting the LLM in capturing graph structure
information. The other involves transforming the graph structure into a sequence
understandable by the LLM or adapting the transformer architecture to concurrently
handle textual and graph structure information, thus eliminating the need for GNNs. (3)
Collaborative solving of LLM and GNN. In this category, LLM and GNN co-solving can be
done in two ways, either by co-training and sharing features, or by aligning the two
through the latent space. In the next section, we will investigate and summarise each of
these three categories individually. A model classification diagram and a representative
example are given as shown in Fig. 1.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Fine Tuning</title>
      <sec id="sec-3-1">
        <title>3.1 GNN as the final component of task solving</title>
        <p>GNN performs well in areas such as processing graph-structured data, but has limitations
in processing graphs with text, whereas LLM possesses a better ability to understand
textual information. In this category, LLM acts as a related device for text feature
extraction, providing initial node feature vectors to the GNN, which later generates node
and edge representations and predictions through the GNN. In the next section, we will
discuss the techniques related to these models.</p>
        <p>GNNs excel in processing graph-structured data but often struggle with graphs
containing textual elements. Conversely, LLMs demonstrate superior capabilities in
understanding text. In this integration, the LLM serves as an auxiliary tool for text feature
extraction, providing initial node feature vectors. These vectors are then further refined by
the GNN, which generates comprehensive node and edge representations and predictions.
The subsequent section will discuss the techniques related to these models in more detail.</p>
        <p>
          LM-GNN [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ] exemplifies the joint training of Large Language Models and Graph Neural
Networks. Here, a graph-aware transformer functions as a semantic encoder, later
finetuned in conjunction with a GNN encoder for predicting links in heterogeneous graphs.
Meng et al. [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ] introduced GNN-LM, a language modeling approach that enhances
traditional neural network language models. It does so by referencing similar contexts
across the entire training corpus, utilizing a high-dimensional tagged representation to
retrieve the k-nearest neighbors of the input context as references. For each input context,
a directed isomorphic graph is constructed, with nodes representing tokens from the input
context or retrieved neighboring contexts and edges signifying connections between these
tokens. A GNN then aggregates information from these contexts to decode the subsequent
token. This methodology facilitates the retrieval of pertinent contexts as references,
thereby improving the model's ability to predict forthcoming words in language modeling
tasks.The LLM-to-LM [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ] framework first wraps the textual attributes associated with each
node in a custom prompt, and then uses the large language model to query and generate a
list of predictions and explanations. Next, the raw text, predictions, and interpretations are
used to fine-tune the language model and turned into vector node features. Finally, these
node features can be used in a downstream graph neural network to predict the classes of
unknown nodes.
        </p>
        <p>
          TextGNN [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] integrates a text encoder with a Graph Neural Network (GNN), showcasing
robust performance in tasks such as advertisement relevance. This model capitalizes on
the text encoder's natural language understanding capabilities and enhances its
performance by incorporating information from graph-type data, outperforming
approaches that rely solely on semantic information. TextGNN employs an end-to-end
framework that synergizes text encoders with Graph Neural Networks for training and
optimization. Within this framework, the text encoder processes textual input, capturing
its semantic essence, while the Graph Neural Network handles graph data, extracting
graph relationships and contextual insights. Xie et al. [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ] proposed a framework model for
graph corpora, in which the framework LM+GNN consists mainly of one or more LMs are
responsible for encoding textual information, while GNN aggregators are used for
information aggregation. Given a graph corpus as input, LM+GNN uses one or more LMs as
text encoders for the nodes. The embeddings generated through these LMs are added to
the topology of the graph and fused with other information in the graph. Finally, the
output is supervised by a task-specific decoder.
        </p>
        <p>
          In comparison to Graph Neural Networks (GNNs), which often depend on high-quality
labeling, Large Language Models (LLMs) boast an extensive knowledge base and exhibit
remarkable zero-shot and few-shot learning capabilities. This is particularly evident in
node classification tasks involving graphs with textual attributes. The integration of an
LLM enables the model to effectively handle node classification tasks even with limited
samples. Traditional GNNs typically require a substantial number of labeled samples to
perform well, posing a challenge in scenarios with limited training data. However, LLMs,
with their extensive pre-training and rich linguistic knowledge acquired from large-scale
textual data, can mitigate this issue. When combined with a GNN, The LLM comprehends
the semantic and contextual nuances of the text, facilitating the generation of high-quality
node representations. LLM-GNN [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ] is an unlabelled node classification method. The
method combines the advantages of graph neural networks and large language models by
using LLM to annotate a small number of nodes and training the GNN on the annotations
of the large language model to predict the majority of unlabelled nodes. Yu et al. [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ]
proposed a method to enhance class-level information using Large Language Models to
improve the quality of node representations, which was used to solve the problem of node
classification tasks under a small number of samples. Semantic information is extracted
from the labels using LLM and samples with labels are generated, whereas the structural
information in the original dataset is later captured using an edge predictor and the newly
generated samples are integrated into the original graph. Finally, the entire dataset is
trained by graph neural network and the results of node classification are obtained. OFA
[
          <xref ref-type="bibr" rid="ref24">24</xref>
          ] describes different graph data through natural language and introduces the concept
of nodes of interest, uses a single task to standardise different tasks, and converts all
inputs embedded in llm into cued graphs containing both graph and task information
through a graphical cueing paradigm, thus allowing adaptive downstream prediction.
Experimentally, OFA was found to be capable of under-shooting and zero-shooting
learning on different graph domains.
        </p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2 LLM as the final component of task solving</title>
        <p>The core concept of this category centers on employing Large Language Models (LLMs) as
the primary architectural framework to acquire both graph structure and textual
information. Given that graphs vary in structure and feature different forms of definitions,
transforming graph data directly into text is not straightforward, posing a significant
challenge for the application of LLMs to graph-related tasks. This category can be further
subdivided based on whether Graph Neural Networks (GNNs) are involved in the
tasksolving process. Accordingly, this section is divided into two subcategories: GNN-free
method and GNN-based methods</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.2.1 GNN-free methods</title>
        <p>
          This type of approach uses LLM directly to obtain textual information and graph structure
without GNN involvement. Traditional LLMs use transformers for natural language
encoding, but have limited ability to model graph structure information. Therefore, this
type of approach obtains node and edge representations by converting the graph structure
into textual information or by designing the LLM as an advanced modelling structure
capable of processing textual information and encoding it graphically. GPT4Graph [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ]
converts graph data into a graphical Description Language. GRAPHTEXT [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ] encodes
graph information into text sequences. InstructGLM [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ] uses natural language to describe
the geometric structure and node characteristics of graphs, and enables LLM to solve
graph-related problems by tuning it with instructions. The above method enables LLM to
process graph data directly by converting graph data into textual descriptions, but LLM
needs to identify the implicit graph structure from sequential text in the process, and
compared with traditional graph learning methods, LLM may face inefficiencies in graph
learning based on sequential graph descriptions, and is still insufficient for representing
multidimensional and correlated graph data.
        </p>
        <p>
          GraphLLM [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ] is an end-to-end approach that synergistically integrates a graph
learning model (graph converter) with an LLM into a single system, with a framework that
consists of three main steps: node understanding, structural understanding, and
LLMoriented prefix tuning for graph enhancement. Compared to methods that convert graph
data to text, GraphLLM is able to improve on graph reasoning tasks by exploiting synergy
with graph converters and leveraging the strengths of both.
        </p>
      </sec>
      <sec id="sec-3-4">
        <title>3.2.2 GNN-based method</title>
        <p>The ability of GNNs to capture hidden representations of structural information between
nodes when processing structured data provides a powerful representation learning
capability. This has led to the utilisation of GNNs in a number of approaches to study LLMs
when processing graph data to enhance the performance of LLMs.</p>
        <p>
          DGTL [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ] utilises large language models to provide prediction and achieve
interpretability for text-attributed graph related tasks, the framework combines a
disentangled graph learning The framework combines the method of untangled graph
learning to generate text embeddings by computing the average of the last layer of
features in the upstream DGTL, capturing the contextual and semantic information of the
text associated with each node, and then using the untangled graph learning to learn
embeddings with different domain information, and then finally injecting the learnt
features with domain information into the downstream DGTL.The LLM and GNN in the
Graph-ToolFormer [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ] framework are individually pre-trained, and then the LLM calls
the pre-trained GNN model to complete the task. That is, LLM is used as a unified common
interface for graph inference tasks.
        </p>
        <p>
          GraphGPT [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ] enhances the understanding and adaptation of graph structures by
aligning them to the natural language space and through graph instruction tuning. In
addition, in order to improve the stepwise reasoning ability of large language models,
GraphGPT also integrates thought chain distillation into the framework, which makes the
whole model show stronger ability in stepwise reasoning and handling distributed
transfer.ReLM [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ] makes use of LM and GNN for chemical reaction prediction, using
pretrained GNNs to generate candidate answers and context examples from a pool of
candidates, which are then analysed in a multiple-choice format using LM.
        </p>
        <p>
          Zou et al. [
          <xref ref-type="bibr" rid="ref28">28</xref>
          ] proposed a new pre-training framework for topology perception by
jointly optimising LM and graph neural networks to predict the nodes involved in the
context graph. In addition, based on the situation that some nodes are rich in textual
information while others have less textual information, an enhancement strategy is
designed to enrich the nodes with text from neighbouring nodes with insufficient textual
information. After finishing the pre-training, only the LM is applied to the downstream
task and the auxiliary role of the GNN is abandoned. PATTON [
          <xref ref-type="bibr" rid="ref31">31</xref>
          ] utilises textual
information and network structure to enhance and consolidate the LM's ability to
comprehend tokens and documents. The GNN nested Transformer architecture
GraphFormers proposed by Yang et al. [32] is used in the framework, while two
pretraining strategies are later employed to help the LM capture the intrinsic dependencies
that exist between textual attributes and network structures.
        </p>
      </sec>
      <sec id="sec-3-5">
        <title>3.3 Collaborative solving of LLM and GNN</title>
        <p>These studies combine GNN for graph structure coding and LLM for textual information
coding for co-training and mutual enhancement.The GNN component can provide
structural information to the whole framework and provide it to LLM, and LLM can
provide textual analysing capability to the whole framework and provide textual signals to
GNN. Depending on how the two combine and learn from each other, we divide this
category into two types: the LLM and GNN predictive alignment, and the LLM and GNN
alignment in potential space.</p>
      </sec>
      <sec id="sec-3-6">
        <title>3.3.1 LLM and GNN Predictive Alignment</title>
        <p>
          GLEM [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ] makes use of the relevant definitions of the Variational EM framework, where
the large language model uses the textual information of each node to predict its labels
and to model the distribution of labels based on local textual attributes. While graph
neural networks use the text and label information of the surrounding nodes to make label
predictions and represent the label distribution under global conditions.GLEM makes the
language model and graph neural networks collaborate with each other by alternating the
optimisation of the E-step and the M-step. Specifically, in the E-step, the graph neural
network is fixed and the language model is made to mimic the label inference of the GNN
in order to transfer the global knowledge learnt by the GNN to the LM.In the M-step, the
LM is fixed and the node representations learnt by the LM are used as features for label
prediction by optimising the GNN. The alternating training of the two steps enables the
GNN to effectively capture the global correlation of nodes and thus achieve accurate label
prediction.
        </p>
        <p>
          Zhang et al. [
          <xref ref-type="bibr" rid="ref15">15</xref>
          ] propose a co-training approach that enables classification and
pseudolabelling of textual attribute maps by combining a text analysis module and a network
learning module. The framework models both the original text and the network structure,
and enhances both modules by co-training and feature sharing.
        </p>
      </sec>
      <sec id="sec-3-7">
        <title>3.3.2 LLM and GNN aligned in potential space</title>
        <p>
          ConGraT [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ] jointly learns graph nodes and text representations by using two
independent encoders that are aligned in a common latent space and training. This
approach receives inspiration from previous work in the area of joint text and image
coding, and extends the training objective to take into account node similarity and
reasonably guessed information.
        </p>
        <p>
          The G2P2 [
          <xref ref-type="bibr" rid="ref17">17</xref>
          ] methodology study utilises a converter-based text encoder and a
GNNbased graphical encoder to improve text classification performance. In this case, the
converter is used as a text encoder and on the other hand, the GNN serves as a graph
encoder taking the graph kernel node features as input and generating node embedding
vectors for each node. By combining the coding capabilities of the converter and the GNN,
the framework is able to provide more comprehensive node representations, and these
node embedding vectors contain both textual information and information about the
graph structure, thus better capturing the semantic and associative relationships between
nodes.
        </p>
        <p>
          Grenade [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ] optimises self-supervised learning algorithms in graphs to capture both
textual semantic and structural contextual information. Grenade exploits the synergistic
effects of pre-trained language models and graph neural networks, and jointly optimises
two self-supervised learning algorithms, graph-centric comparison learning and
graphcentric knowledge alignment.
        </p>
        <p>
          GraD [
          <xref ref-type="bibr" rid="ref30">30</xref>
          ] encodes graph structures into LMs for fast inference without graphs, and
joint training of teacher GNNs and students without graphs through shared LMs allows the
two models to learn from each other and improve overall performance.
        </p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Challenges and future directions</title>
      <p>While the preceding sections have outlined the current landscape of using language
models in graph learning, there remains significant potential for further research in this
domain. In this section, we briefly examine some limitations of language models when
applied to graph learning and suggest potential directions for future research.</p>
      <p>Lack of effective pre-training algorithms. most current language models are based on
self-supervised pre-training, but this approach is not effective in graph learning. Therefore,
it remains a challenge to effectively pre-train on large-scale graph data. Exploring
pretraining methods on graphs is a valuable research direction.</p>
      <p>Insufficient ability to represent structural information. since the training is mainly
based on textual data, language models lack in grasping the complexity of graph structural
information, and generating topology-based supervised signals using language models is a
challenging problem. A way to address this problem could be by designing specific
pretraining goals to guide the language model to learn the representation of topological
structures.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Conclusion</title>
      <p>The application of Large Language Models (LLMs) to graph-related tasks has emerged as a
vital research area in recent years. To classify and provide a comprehensive overview of
this field, we propose a novel classification method. This method categorizes techniques
involving graphs and textual information into three distinct categories:LLMs as the final
component of task solving, GNNs as the final component of task solving, and collaborative
solving of LLM and GNN. Based on this categorisation, we systematically review
representative studies and discuss some limitations and future research directions in this
direction. It is hoped that this comprehensive review will reveal the potential of LLM in
the field of graph learning, as well as the advances and challenges made, and provide
insights for further developments in the field.
[32] J. Yang, Z. Liu, S. Xiao, C. Li, D. Lian, S. Agrawal, et al., “GraphFormers: GNN-nested
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