A few weeks ago I playfully suggested that the Democratic nominee for POTUS might be selected this year by a game of hex played on the map of the lower 48 states. I emphasize the word “playfully.” This was not a serious suggestion. But life has a way of overtaking us, even in our most […]

The interesting thread of comments on Wednesday’s post about “electoral hex” led me to look more closely at the graph for the Lower 48 states:

I’ve constructed the graph—and it wasn’t easy, by the way—on the rule that two states are linked by an edge if they share a common boundary of more than one point. […]

Democrats here in the U.S. are having quite a primary season. With high hopes of winning the general election in November, we are deadlocked over which candidate to nominate. Should we just wait to let the delegates slug it out at the convention in August? Should the trailing candidate withdraw in the interest of party […]

The answer to the question in the headline is: Too many. After I wrote about Sudoku a couple a years ago, I thought I had cured my addiction; but I’ve been a shameless backslider.
I return to the subject now, in this public confessional mode, to correct an error in my 2006 column. Citing a […]

Don Elgee, a retired teacher of mathematics and computer science from Ottawa, sends the following inquiry:

In hockey, when a team is down by a goal with about one minute to go, the goalie is pulled in favor of another offensive player. This illustrates a key point in the strategy of most games.
The object is not […]

Among the 250 million Rubik’s cubes manufactured since 1980, how many lie abandoned in a scrambled state, having never regained their original configuration since being taken out of the box? Most of them, I would guess. Now comes word that those cubes might be restored to pristinity with a little less effort. The upper bound […]

This is a belated update to my most recent post (which is not at all recent!). If you recall, we were discussing simple playground protocols for assigning players to teams. In one case the captains of teams A and B choose players in the order ABAB…; the alternative order is ABBA…. I presented some simulation […]

A while ago I wrote about the playground ritual of choosing teams for a ball game. The simplest algorithm has two captains, A and B, who take turns choosing players until everyone is assigned to one team or the other. Call this the ABAB algorithm. Donald B. Aulenbach suggested a very easy modification that produces […]

A few weeks ago I commented on the discovery of some curious precursors of Sudoku, drawn up in the 1950s as designs for agricultural experiments. Now even earlier antecedants of the puzzle have been discovered by Christian Boyer, a specialist in recreational mathematics. Writing in the French magazine Pour la Science, Boyer describes and reproduces […]

The invention of the puzzle we now call Sudoku is generally credited to Howard Garns, an architect from Indianapolis. His first puzzles, which were known then as Number Place, were published in 1979. But now a curious precedent has turned up. More than 20 years earlier, in the 1950s, W. U. Behrens of Hannover, Germany, […]