## Saturday, April 5, 2014

### Logic in limericks

In these lines, Sandra DeLozier Coleman (who participated in the math-poetry reading at the Joint Mathematics Meetings in Baltimore in January) speaks as a professor reasoning in rhyme, explaining truth-value technicalities of the logical implication, "If p then q" (or, in notation, p -- > q ).

The Implications of Logic

That p --> q is true,
Doesn’t say very much about q.
For if p should be false,
Then there’s really no loss
In assuming that q could be, too.

On the other hand q could be true.
So, what is a body to do?
With a false antecedent,
The consequent needn’t
Be something one lends credence to!

If the whole statement’s false, then, my dear,
There is no ambiguity here!
For then p must be true,
But then not so for q.
I do hope that’s all perfectly clear!

This professorial voice that Coleman sometimes inhabits also may be found here in another poem -- this one in Evelyn Lamb's Scientific American blog, "Roots of Unity" --  a poem that explains the abstract algebraic concept of "group."  Implications, alternatively termed "conditionals," are explored also in this post -- which contains poems by Romanian poet Marin Sorescu and me.