general artificial intelligence workshop
Improving exploration in policy gradient search: Application to symbolic optimization
Larma, Mikel Landajuela, Petersen, Brenden K., Kim, Soo K., Santiago, Claudio P., Glatt, Ruben, Mundhenk, T. Nathan, Pettit, Jacob F., Faissol, Daniel M.
Many machine learning strategies designed to automate mathematical tasks leverage neural networks to search large combinatorial spaces of mathematical symbols. In contrast to traditional evolutionary approaches, using a neural network at the core of the search allows learning higher-level symbolic patterns, providing an informed direction to guide the search. When no labeled data is available, such networks can still be trained using reinforcement learning. However, we demonstrate that this approach can suffer from an early commitment phenomenon and from initialization bias, both of which limit exploration. We present two exploration methods to tackle these issues, building upon ideas of entropy regularization and distribution initialization. We show that these techniques can improve the performance, increase sample efficiency, and lower the complexity of solutions for the task of symbolic regression.
Analyzing the Nuances of Transformers' Polynomial Simplification Abilities
Agarwal, Vishesh, Aditya, Somak, Goyal, Navin
Symbolic Mathematical tasks such as integration often require multiple well-defined steps and understanding of sub-tasks to reach a solution. To understand Transformers' abilities in such tasks in a fine-grained manner, we deviate from traditional end-to-end settings, and explore a step-wise polynomial simplification task. Polynomials can be written in a simple normal form as a sum of monomials which are ordered in a lexicographic order. For a polynomial which is not necessarily in this normal form, a sequence of simplification steps is applied to reach the fully simplified (i.e., in the normal form) polynomial. We propose a synthetic Polynomial dataset generation algorithm that generates polynomials with unique proof steps. Through varying coefficient configurations, input representation, proof granularity, and extensive hyper-parameter tuning, we observe that Transformers consistently struggle with numeric multiplication. We explore two ways to mitigate this: Curriculum Learning and a Symbolic Calculator approach (where the numeric operations are offloaded to a calculator). Both approaches provide significant gains over the vanilla Transformers-based baseline.
The Role of General Intelligence in Mathematical Reasoning
It offers optimality principles that govern the blending process. Blending has in particular been used to account for concepts in mathematics as well (Lakoff & Nรบรฑez, 2000; Guhe et al., 2011). Various computational implementations have followed the cognitive theory, formalizing its notions and principles (Eppe et al., 2018); and even a theoretical Category Theoretic formulation that unifies these various A.I. concretizations (Schorlemmer & Plaza, 2021). The phenomenon explored here, however, is treated as a very high-level (and rather peripheral) conceptual one, concerning (perhaps human-only) creativity. And the computational implementations are grounded in logic, accordingly. The different focus I suggest here is on such combination as a fundamental component of the cognitive construction of object-representations at large. In particular, how the regularities that govern the possibility and value of such combinations are handled, should be understood as part of the more general working of the system, picking up on and integrating statistical patterns into the construction of its ontology. In terms of A.I., this reflect the on-going quest to find the proper place for the symbolic within modern architectures, which are chiefly neural. Given the suggested picture, of how an object-centered system might in general come to attribute objecthood or break it apart, we can approach the development of our conception of numbers and account for a hidden, sub-symbolic intricacy in that conception.
Distilling Wikipedia mathematical knowledge into neural network models
Kim, Joanne T., Larma, Mikel Landajuela, Petersen, Brenden K.
Machine learning applications to symbolic mathematics are becoming increasingly popular, yet there lacks a centralized source of real-world symbolic expressions to be used as training data. In contrast, the field of natural language processing leverages resources like Wikipedia that provide enormous amounts of realworld textual data. Adopting the philosophy of "mathematics as language," we bridge this gap by introducing a pipeline for distilling mathematical expressions embedded in Wikipedia into symbolic encodings to be used in downstream machine learning tasks. We demonstrate that a mathematical language model trained on this "corpus" of expressions can be used as a prior to improve the performance of neural-guided search for the task of symbolic regression. "The basis of all human culture is language, and mathematics is a special kind of linguistic activity."
Investigating the Limitations of Transformers with Simple Arithmetic Tasks
Nogueira, Rodrigo, Jiang, Zhiying, Lin, Jimmy
The ability to perform arithmetic tasks is a remarkable trait of human intelligence and might form a critical component of more complex reasoning tasks. In this work, we investigate if the surface form of a number has any influence on how sequence-to-sequence language models learn simple arithmetic tasks such as addition and subtraction across a wide range of values. We find that how a number is represented in its surface form has a strong influence on the model's accuracy. In particular, the model fails to learn addition of five-digit numbers when using subwords (e.g., "32"), and it struggles to learn with character-level representations (e.g., "3 2"). By introducing position tokens (e.g., "3 10e1 2"), the model learns to accurately add and subtract numbers up to 60 digits. We conclude that modern pretrained language models can easily learn arithmetic from very few examples, as long as we use the proper surface representation. This result bolsters evidence that subword tokenizers and positional encodings are components in current transformer designs that might need improvement. Moreover, we show that regardless of the number of parameters and training examples, models cannot seem to learn addition rules that are independent of the length of the numbers seen during training. Abstraction and composition are two important themes in the study of human languages, made possible by different linguistic representations. Although treatments in different linguistic traditions vary, representations at the lexical, syntactic, and semantic levels are a common feature in nearly all theoretical studies of human language, and until relatively recently, these representations are explicitly "materialized" in language processing pipelines (for example, semantic role labeling takes as input a syntactic parse).