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Finite abelian groups

We defined a finite group in an earlier article. It is a finite set G with an operation, usually written as a product, so that the product of a and b is ab, which satisfies a few simple axioms. The group is abelian if this operation is commutative, so that we always have ba = [...]

Independent Safeguarding Authority (2)

The early history was given in the earlier article. The original Rehabilitation of Offenders Act 1974 offered some protection for individuals against intrusive questioning by insurance companies and others. Insurance contracts are “uberimae fidei” meaning “of the utmost good faith”. In other words the individual has a duty to disclose anything that might be relevant [...]

Blind as bats

I enjoy City AM, the free paper daily paper (Mo-Fr) distributed in parts of London, but it is firmly aimed at bankers and others working in financial services. A couple of weeks ago most papers had headlines like i‘s (on the right below), but City AM (on the left) went the other way: Of course, [...]

Solution to group puzzles (2)

We noticed in the two earlier articles (here and here) that it is not obvious how to prove that a particular operation satisfies the associative law. One way is to use the idea of generators. For example, we noticed that the group can be regarded as generated by a, b with a2 = b3 = [...]

Independent Safeguarding Authority (1)

One of the headlines today is that the Met’s investigations into the disappearance of Madeleine McCann have now cost £2 million with no end in sight. It is hard not to be cynical about this. The saga has certainly sold far more than £2 million worth of tabloid newspapers. Madeleine, then 3, disappeared almost 5 [...]