Groups (11)
And finally ...
Multiplying all whole numbers and fractions together will give
us a group provided that we exclude that tricky number zero, which turns
every other number it multiplies into zero as well, a sort of mathematical
kiss of death.
There are many other kinds of infinite group. For example, repeating
patterns and their shifts give infinite groups.
Here's an example of this. (you have to imagine that the pattern extends
infinitely in both directions.)
Shifting the unit of repeat to the right or to the left works in exactly
the same way as adding whole numbers.
Looking forward
The huge importance of groups in scientific applications comes from being
able to apply their shared mathematical properties to
the many different kinds of physical
situation which share the same mathematical structure.
Groups have been found which are at the cutting edge of theories which
describe the behaviour of the physical world, so this is exciting both
scientifically and mathematically.

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