Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: TimeTraveler: Reinforcement Learning for Temporal Knowledge Graph
  Forecasting   Temporal knowledge graph (TKG) reasoning is a crucial task that has gained
increasing research interest in recent years. Most existing methods focus on
reasoning at past timestamps to complete the missing facts, and there are only
a few works of reasoning on known TKGs to forecast future facts. Compared with
the completion task, the forecasting task is more difficult that faces two main
challenges: (1) how to effectively model the time information to handle future
timestamps? (2) how to make inductive inference to handle previously unseen
entities that emerge over time? To address these challenges, we propose the
first reinforcement learning method for forecasting. Specifically, the agent
travels on historical knowledge graph snapshots to search for the answer. Our
method defines a relative time encoding function to capture the timespan
information, and we design a novel time-shaped reward based on Dirichlet
distribution to guide the model learning. Furthermore, we propose a novel
representation method for unseen entities to improve the inductive inference
ability of the model. We evaluate our method for this link prediction task at
future timestamps. Extensive experiments on four benchmark datasets demonstrate
substantial performance improvement meanwhile with higher explainability, less
calculation, and fewer parameters when compared with existing state-of-the-art
methods.

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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga