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Governments develop policies to reduce unwarranted inequalities in society. Hence, there is a need for well-founded measures of inequality to monitor the impact of such policies. The discipline of economics has developed many such measures over the last century. Although these measures have focused on measuring inequality of incomes, they can be adapted to other economic variables. In this multidisciplinary, review paper, we present an introduction to measures of economic inequality from a mathematical perspective, and highlight their policy implications. This is an area in which mathematics and economics can contribute to justice and fairness in society.

Tree diagrams arise naturally in courses on probability at high school or university, even at an elementary level. Often they are used to depict outcomes and associated probabilities from a sequence of games. A subtle issue is whether or not the Markov condition holds in the sequence of games. We present two examples that illustrate the importance of this issue. Suggestions as to how these examples may be used in a classroom are offered.

Selective assembly is applied to produce high-precision assemblies from relatively low-precision components of partitioning mating parts and performing random assembly between corresponding groups. The traditional approach only ensures that the required..

A questionnaire was sent to 700 optical and optometrical practices in Hong Kong in February 1992 to survey the state of contact lens practice in Hong Kong for the year 1991. There were 174 replies. During the year surveyed, each respondent fitted an average of 540 patients with contact lenses, 44 per cent of which were refits. Of all the contact lenses fitted, 86.9 per cent were soft contact lenses, 8.8 per cent were rigid gas permeable lenses and 4.4 per cent were PMMA lenses. Eighty per cent of the practices dispensed extended or flexible wear contact lenses and, on average, the maximum period of continuous wear recommended was 4.8 days. The most popular soft lens disinfecting regime recommended was the hydrogen peroxide system, and most respondents recommended mechanical rubbing of lenses during daily cleaning, irrespective of the disinfecting regime used. Compared to the previous survey, the results showed a continued low usage of speciality lens types, although there was increased usage of toric lenses.

The Kidnappers Slide complex, on the 1–5° upper continental slope of eastern North Island, New Zealand, consists of several, very large translational slides and rotational slumps. They are of several Late Quaternary phases, range from 20 to 140 m thick, and cover a total area of 720 km2. The main, early Holocene (c. 8000–10,000 yr) phase involved a coast‐parallel sedimentary prism that was deposited on the outer shelf and upper continental slope at a rate of 1–3 m/1000 yr during the last glacial age. Irregularly blanketing the slump, and also locally slumped, is the thin, outer edge of the post‐glacial (< 16,000 yr) prism, deposited on the upper slope at rates ranging from 0.3 to 0.7 m/1000 yr. The sediments consist essentially of terrigenous hemipelagic olive gray mud, along with minor sandy mud, volcanic ash, and pumiceous mud. They are low in calcium carbonate and are inorganic, with high plasticity and low sensitivity. Minor variations occur in the mass physical properties of the post‐glacial...