Tax law improvement in Australia and the UK: the need for a strategy for simplification

In both Australia and the UK, programmes are under way to simplify tax legislation by rewriting it. This paper demonstrates that tax simplification is a complicated concept and concludes that sustainable improvement is unlikely to be achieved if reform is limited only to linguistic changes. Tax law is complicated because there are powerful pressures that tend to increase the complexity of modern tax systems and these should also be considered in any simplification programme. In addition, tax simplification may be promoted by the greater use of purposive legislation — that is, legislation drafted in terms of general principles rather than much more comprehensive legislation designed to deal with every likely possibility. The paper examines the progress of the Australian Tax Law Improvement Project and argues that what is needed is a strategy for tax simplification that is incorporated into the process of generating tax policy itself.

Interactive Simplifier Tracing and Debugging in Isabelle

The Isabelle proof assistant comes equipped with a very powerful tactic for term simplification. While tremendously useful, the results of simplifying a term do not always match the user's expectation: sometimes, the resulting term is not in the form the user expected, or the simplifier fails to apply a rule. We describe a new, interactive tracing facility which offers insight into the hierarchical structure of the simplification with user-defined filtering, memoization and search. The new simplifier trace is integrated into the Isabelle/jEdit Prover IDE.Comment: Conferences on Intelligent Computer Mathematics, 201

PyZX: Large Scale Automated Diagrammatic Reasoning

The ZX-calculus is a graphical language for reasoning about ZX-diagrams, a type of tensor networks that can represent arbitrary linear maps between qubits. Using the ZX-calculus, we can intuitively reason about quantum theory, and optimise and validate quantum circuits. In this paper we introduce PyZX, an open source library for automated reasoning with large ZX-diagrams. We give a brief introduction to the ZX-calculus, then show how PyZX implements methods for circuit optimisation, equality validation, and visualisation and how it can be used in tandem with other software. We end with a set of challenges that when solved would enhance the utility of automated diagrammatic reasoning.Comment: In Proceedings QPL 2019, arXiv:2004.1475

On the Origin of the Quantum Rules for Identical Particles

We present a proof of the Symmetrization Postulate for the special case of noninteracting, identical particles. The proof is given in the context of the Feynman formalism of Quantum Mechanics, and builds upon the work of Goyal, Knuth and Skilling (Phys. Rev. A 81, 022109 (2010)), which shows how to derive Feynman's rules from operational assumptions concerning experiments. Our proof is inspired by an attempt to derive this result due to Tikochinsky (Phys. Rev. A 37, 3553 (1988)), but substantially improves upon his argument, by clarifying the nature of the subject matter, by improving notation, and by avoiding strong, abstract assumptions such as analyticity.Comment: 8 pages, all figures embedded as TikZ. V2 clarified wording from V1 in response to reviewe

The readability of Australia’s taxation laws and supplemetary materials: an empirical investigation

Australian taxation law has been criticised for many years for its difficulty to read and understand. The Tax Law Improvement Project (TLIP) was established in December 1993 to rewrite in plain language Australia’s income tax legislation. The primary purpose of this study is to test empirically the effectiveness of attempts at simplifying the Income Tax Assessment Act 1936 as amended. The study utilises empirical measures in analysing the level of readability of Australia’s taxation laws. In doing so, it builds on earlier research, which applied similar methods in examining the New Zealand taxation simplification process. It was found that the sections of Income Tax Assessment Act 1997 sampled were slightly more readable than corresponding sections of Income Tax Assessment Act 1936 as amended, which is consistent with Wallschutzky’s (1995) findings. Nevertheless, the results fall well short of acceptable bench-marks, suggesting that the goal of simplification has not been achieved.