## GAA Clustering

Posted in Bad Statistics, GAA, The Universe and Stuff with tags , , , , , , on July 25, 2022 by telescoper

The above picture was doing the rounds on Twitter yesterday ahead of this year’s All-Ireland Football Final at Croke Park (won by favourites Kerry despite a valiant effort from Galway, who led for much of the game and didn’t play at all like underdogs).

The picture above shows the distribution of Gaelic Athletics Association (GAA) grounds around Ireland. In case you didn’t know, Hurling and Gaelic Football are played on the same pitch with the same goals and markings on the field. First thing you notice is that the grounds are plentiful! Obviously the distribution is clustered around major population centres – Dublin, Cork, Limerick and Galway are particularly clear – but other than that the distribution is quite uniform, though in less populated areas the grounds tend to be less densely packed.

The eye is also drawn to filamentary features, probably related to major arterial roads. People need to be able to get to the grounds, after all. Or am I reading too much into these apparent structures? The eye is notoriously keen to see patterns where none really exist, a point I’ve made repeatedly on this blog in the context of galaxy clustering.

The statistical description of clustered point patterns is a fascinating subject, because it makes contact with the way in which our eyes and brain perceive pattern. I’ve spent a large part of my research career trying to figure out efficient ways of quantifying pattern in an objective way and I can tell you it’s not easy, especially when the data are prone to systematic errors and glitches. I can only touch on the subject here, but to see what I am talking about look at the two patterns below:

You will have to take my word for it that one of these is a realization of a two-dimensional Poisson point process and the other contains correlations between the points. One therefore has a real pattern to it, and one is a realization of a completely unstructured random process.

I show this example in popular talks and get the audience to vote on which one is the random one. The vast majority usually think that the one on the right that  is random and the one on the left is the one with structure to it. It is not hard to see why. The right-hand pattern is very smooth (what one would naively expect for a constant probability of finding a point at any position in the two-dimensional space) , whereas the left-hand one seems to offer a profusion of linear, filamentary features and densely concentrated clusters.

In fact, it’s the picture on the left that was generated by a Poisson process using a  Monte Carlo random number generator. All the structure that is visually apparent is imposed by our own sensory apparatus, which has evolved to be so good at discerning patterns that it finds them when they’re not even there!

The right-hand process is also generated by a Monte Carlo technique, but the algorithm is more complicated. In this case the presence of a point at some location suppresses the probability of having other points in the vicinity. Each event has a zone of avoidance around it; the points are therefore anticorrelated. The result of this is that the pattern is much smoother than a truly random process should be. In fact, this simulation has nothing to do with galaxy clustering really. The algorithm used to generate it was meant to mimic the behaviour of glow-worms which tend to eat each other if they get  too close. That’s why they spread themselves out in space more uniformly than in the random pattern.

Incidentally, I got both pictures from Stephen Jay Gould’s collection of essays Bully for Brontosaurus and used them, with appropriate credit and copyright permission, in my own book From Cosmos to Chaos.

The tendency to find things that are not there is quite well known to astronomers. The constellations which we all recognize so easily are not physical associations of stars, but are just chance alignments on the sky of things at vastly different distances in space. That is not to say that they are random, but the pattern they form is not caused by direct correlations between the stars. Galaxies form real three-dimensional physical associations through their direct gravitational effect on one another.

People are actually pretty hopeless at understanding what “really” random processes look like, probably because the word random is used so often in very imprecise ways and they don’t know what it means in a specific context like this.  The point about random processes, even simpler ones like repeated tossing of a coin, is that coincidences happen much more frequently than one might suppose.

I suppose there is an evolutionary reason why our brains like to impose order on things in a general way. More specifically scientists often use perceived patterns in order to construct hypotheses. However these hypotheses must be tested objectively and often the initial impressions turn out to be figments of the imagination, like the canals on Mars.

## The All-Ireland Senior Hurling Championship Final

Posted in GAA with tags , , , , on July 17, 2022 by telescoper

Today’s the day! Kilkenny v Limerick from Croke Park for the All-Ireland Senior Hurling Championship Final. Over 80,000 spectators will watch this in Croke Park as well as millions around the world. Let’s hope it’s a good one.

Half Time: Kilkenny 0-16 Limerick 1-17

Reasonably comfortable for Limerick who have been ahead since the 2nd minute. Can Kilkenny fight back in the 2nd half? I’m glad for the sake of the players that it’s “only” 27 °C at Croke Park this afternoon and not even hotter!

Full Time: Kilkenny 2-26 Limerick 1-31

So Limerick have won their 3rd All-Ireland Championship in a row by just two points.

Kilkenny scored two goals in the second half to level the scores at which point Limerick seemed a bit ragged, but Limerick pulled themselves together held on for the victory in what was a thrilling second half. Hurling is not a game for faint hearts but alongside the physicality of the game there is an astonishing level skill: the accuracy of the long-range shooting is quite phenomenal.

Congratulations to Limerick, deserved winners, and commiserations to Kilkenny who made a fantastic game of it. What a magnificent final.

## The 2021 All-Ireland Senior Hurling Final

Posted in GAA with tags , , , , on August 22, 2021 by telescoper

This afternoon’s All-Ireland Senior Hurling Championship Final at Croke Park saw reigning champions Limerick beat Cork by 3-32 to 1-22 at Croke Park. The margin of victory (16 points) reflected Limerick’s dominance; their total of 41 points is one of the largest ever in a final. The Bookies were right in having Limerick odds-on favourites (1-5) before the match and they thoroughly deserved their victory. Congratulations to them!

As a neutral I was hoping for a less one-sided match, and Cork actually started off quite well, responding quickly to Limerick’s opening goal with an impressive goal of their own. The game started at a frantic pace and for about ten minutes it looked a pretty even contest, but once Limerick got into their stride they imposed themselves on all areas of the game. The Limerick team not only looked physically bigger than their opponents but also put in a phenomenal work rate, to such an extent that it frequently seemed they had more players on the pitch than Cork. I know it’s a cliché, but at times it really did look like men against boys.

When not in possession, Limerick harried their opponents into making mistakes and when in possession they ruthlessly exploited errors in the Cork defence. In particular they exerted their trademark dominance of the middle third of the pitch, scoring points from long range like a boxer with a longer reach than his opponent and making it very difficult for Cork to play through them. By half time, when the score was 1-11 to 3-18, Limerick were already 13 points ahead and the game was effectively over as a contest. It was more like an exhibition match or some sort of masterclass.

Credit to the young Cork side for the way they stuck to their task despite being comprehensively outplayed. There’s no disgrace in losing to a team as good as the one they played today. In the end, though, the Championship title goes once again to Limerick, who were magnificent.

Incidentally, Croke Park was about half-full for this showcase event with about 40,000 spectators in the ground. Hopefully next year it will be possible to fill it to capacity. I watched it on TV but it makes a huge difference to the atmosphere if there’s a big crowd watching it in the stadium.

## Pronouns for Yous

Posted in Biographical, GAA, Television with tags , , , , , on August 21, 2021 by telescoper

Last night I was watching a very interesting television programme on the Irish language channel TG4. It was about the origins and history of ice hockey, which began as ice hurling as a sport played by Irish immigrants in Canada. The word “puck” comes from the Irish word poc which means to stroke or hit; in hurling the “puck out” is a free hit from the goal area by the goalkeeper much like a goal kick in soccer. The programme was called Poc na nGael, which roughly translates as “The Puck of the Irish”. I think it was repeated last night because this Sunday sees the biggest event of the year in the hurling calendar: the Final of the All-Ireland Senior Hurling Championship at Croke Park, which this year is between Limerick and Cork.

While watching that programme I got thinking about Irish language lessons and whether I will have time to continue them next academic year and then onto wider issues about differences between Irish and English. One thing that struck me was the second person pronoun, so I thought I’d do the following rambling post about it.

In English the personal pronouns I (first person) and he/she (third person) are unusual in that they change depending on their grammatical role. This isn’t unusual in other languages especially Latin where it is the rule rather than the exception. In English we use “I” in the nominative case (“I hit the dog”) but “me” in the accusative case (“the dog bit me”) or when following a preposition (“the dog gave the stick to me”). The same goes with he/him and she/her.

In the example “the dog gave the stick to me”, “me” is really in the dative case but there is no distinct word for that in English; we can only really distinguish between the nominative (subject) and “other” (non-subject) cases. The words “my”, “our”, etc are often called pronouns but they are really of adjectival form, e.g. “this is my cat” and are more correctly called determiners. There are possessive pronouns (“mine”, “ours”, etc) which are in some sense genitive cases of the personal pronouns (meaning “of me”, “of us”, etc) but I digress.

Notice also that the first person and third person plural also have distinct plural forms (we/us and they/them).

The funny one is the second person “you”, which has neither an accusative nor prepositional form nor a distinct plural: “You hit the dog”, “the dog bit you” and “the dog gave the stick to you” all employ the same word although each is in a different grammatical case.

This is by no means the only oddity in modern English, and I have no idea why it developed. In older forms of English there were distinct forms: “thou/thee” in the singular and “ye/you” in the plural. These forms persist in dialects such as Yorkshire.

For some reason, though, as English evolved these four distinct forms merged into one, i.e. “you”. One can usually tell from the context whether “you” is singular or plural or can emphasize it by adding extra words (e.g. in the American “y’all” which is a contraction of “you all”) but there is no single word in standard English that expresses the difference between singular and plural or between subject and non-subject.

Incidentally, in Irish the second person singular is in the nominative case and thú in the non-nominative cases; the second person plural is sibh which is like “ye” in that it has no distinct non-nominative form.

I was brought up on Tyneside and it is a feature of the Geordie dialect that people use the word “yous” to denote the second person plural. It’s definitely a working-class slang, and was very much frowned upon at school, but it was very commonplace when and where I was grew up. I thought it was only in Newcastle that people used this form but when I worked at Sussex a while ago my boss, originally from Glasgow, also on occasion used “yous”. When I asked here about it she explained that it was common usage in Glasgow but didn’t think it was widespread in other parts of Scotland. Geordie and Glaswegian are thus two regional dialects I know that use this form but there may be others. I’d be interested to know so please feel free to comment via the box below!

Anyway the reason for going off on this tangent was that I’d already noticed that a few Irish people use “ye” in Hiberno-English for the second person plural, it was only yesterday that I noticed some using “yous”. I wonder how widespread that is in Ireland and is it regional or more of a class divide?

Would any of yous like to comment?

## Back to Civilisation

Posted in Biographical, Cardiff, Covid-19, Cricket, GAA, Maynooth with tags , , , on July 24, 2021 by telescoper

So last night I returned safely from Cardiff to Ireland via Birmingham. Travel both ways was relatively uneventful. There can’t have been more than 30 people on the flight in either direction. I did however almost screw up the return flight by omitting to fill in the obligatory Covid-19 passenger locator form which I hadn’t realised is now online-only. I only found out that I had to do it before they would let me on the plane, resulting in a mad scramble with a poor phone connection to get it done. After a few goes and quite a bit of stress I succeeded and was allowed to board, conspicuously the last passenger to do so. We still managed to leave early though, and the short flight to Dublin – passing directly over Ynys Môn was relaxing and arrived on schedule; the immigration officer scanned my new-fangled Covid-19 vaccination certificate but wasn’t interested in the passenger locator form that caused me so much stress on departure.

I returned to Cardiff to take a bit of a break, to check up on my house and also prepare to move the rest of my belongings to Ireland. I was relieved when I got there last week that everything was basically in order, although there were lots of cobwebs and a very musty smell, which was hardly surprising since I hadn’t been there for 15 months. The inside of the fridge wasn’t a pretty sight either.

One night last week after meeting some friends for a beer in Cardiff I walked back via Pontcanna Fields and saw, much to my surprise, Camogie practice in progress in the twilight:

The logistics of my planned removal proved a bit more complicated than I expected but eventually I cracked it and all the arrangements are now in place. I should receive delivery here in Maynooth next month. I’m doing it on the cheap as a part-load, which is why it will take a bit longer than usual.

Cleaning and packing was very hard work owing to the intense heat over the last week or so – it was regularly over 30° C – during the day, so I took quite a few siestas. My neighbours tell me it’s been much the same here in Maynooth, although it is a bit cooler today, around 20° with a very pleasant breeze.

Despite the hard work it was nice to have a change of scenery for a bit and also to meet up with some old friends from Cardiff days. Everyone has been in a state of limbo for the last 18 months or so, and although we’re not out of the woods yet there are signs of things coming back to life. When I went to Bubs in Cardiff for a drink last week it was the first time I’d been inside a pub since February 2020!

Incidentally, most people I saw observed social distancing, wore masks, etc. The rules in Wales are still fairly strict. Although open for indoor service, bars and restaurants seem to have few customers. Some people on trains to and from Birmingham didn’t wear masks. One group of unmasked and obnoxious English passengers on my return journey were loudly boasting how backwards Wales was compared to England, where the rules have relaxed despite a huge surge in cases. I moved to another carriage.

The only other thing I managed to do was attend a Royal London One-Day Cup match at Sophia Gardens between Glamorgan and Warwickshire in the baking heat of Sophia Gardens. It turned out to be a good tight game, with Glamorgan winning by 2 wickets courtesy of two consecutive boundaries. Most of the time I was sitting there in the shade I was thinking how glad I was not to be fielding in such conditions.

One thing that was very noticeable during my stay in Wales was that it was very hard to get fresh salad vegetables and the like. That may be partly due to weather-related demand or it may be due to a shortage of lorry drivers or other staff owing to Covid-19 isolation requirements and may be a consequence of Brexit. Who knows? I’ll just say that there’s been hot weather in Ireland, where the Covid-19 pandemic is also happening but there are no reports of shortages of fresh food here. I’m very much looking forward to having a nice salad with my dinner this evening.

Anyway, I suppose that’s enough rambling. At some point I’ll have to open up my email box to see what horrors lurk therein. Still can’t be worse than the fridge I opened last week. Can it?

## Football Round Up

Posted in Football, GAA on May 23, 2021 by telescoper

Well today saw the last round of matches of the English Premier League for this season. The most important match finished Fulham 0 Newcastle United 2. That caps a good end of season run that leaves Newcastle in 12th place having recovered well from an alarming slump in mid-season to avoid any threat of regation.

It’s been a good weekend for Newcastle fans because yesterday Sunderland lost their playoff semi-final against Lincoln City and therefore languish in League One for another season.

Fulham, West Brom were already relegated some time ago, so there wasn’t much end of season drama at the bottom end of the table. I gather that manager Sam Allardyce will be leaving West Brom, having accomplished everything that was expected of him with the club.

As you can see, the top three teams are all from the Midlands. Leicester could have joined them had they not lost to Spurs today so it is Chelsea that joins them in the top 4. Manchester City finish as Champions by a country mile.

By contrast, here in Ireland, the Gaelic Football season has only just started. This afternoon I watched a cracking game between Dublin and Kerry that ended with points level at 4-09 to 1-18 after a late penalty to Kerry allowed them to equalize in stoppage time. Dublin had been well ahead earlier in the game but had to weather a determined fightback to hold on for the draw.

There are no crowds at GAA matches yet but at least one can watch games for free on terrestrial TV…

## All-Ireland Hurling Final Day

Posted in GAA with tags , , , , , on December 13, 2020 by telescoper

As the absurd Pantomime of Brexit negotiations continues and I prepare for a very busy final week of an exhausting term I’m taking this afternoon off to watch the final of the All Ireland Senior Hurling Championship from Croke Park in Dublin. The final is between Limerick and Waterford, and is in effect a re-run of the 2020 Munster provincial final, which was won by Limerick. (The winners of the Leinster and Munster Provincial championships go straight into the semi-finals of the All-Ireland Championship, while the runners-up play in the Quarter-Finals).

The All-Ireland Senior Hurling Final usually takes place in August or September, but this year’s competition has been rescheduled because of the Covid-19 pandemic.

It was raining very heavily overnight and into this morning in the Dublin are but the bad weather has cleared so I’m looking forward to a good match. According to the bookies, Limerick are strong favourites at 4/9 with Waterford at 5/2. Throw-in is at 3.30pm. The match will be played in a largely empty Croke Park, which means the atmosphere won’t be the same as in front of a crowd of 80,000 but I hope it will be enjoyable nonetheless. I’m not going to live blog the match but will update at half time and at the end.

As a bonus, the main event is preceded by the final of the Joe McDonagh Cup which is the second tier of the All-Ireland Senior Hurling Championship. This year’s final is between Antrim and Kerry. Antrim were strong favourites before the match and began the match better of the two teams, but Kerry fought back well from a poor start to lead 1-07 to 0-9 at half time.

UPDATE: Half-time Limerick 0-14 Waterford 0-11. The scoreline doesn’t really reflect Limerick’s dominance, but Waterford are doing well to stay in the game. Only three points in it. I still think Limerick will win.

UPDATE: Full-time Limerick 0-30 Waterford 0-19. Limerick just too strong for Waterford, who had no answer to the relentless accuracy of Limerick’s shooting from long range. Limerick’s defence also impressive, nullifying the threat from Waterford’s full forwards. Congratulations to Limerick.

Yesterday’s Irish Times prediction has aged well…

## Another Week Ending

Posted in Biographical, Covid-19, Education, GAA, Maynooth, The Universe and Stuff on December 4, 2020 by telescoper

As this term staggers on I once again arrive at a weekend in a state of exhaustion. Still there are just two teaching weeks left for this term so soon it will be the Christmas break. At least there won’t be any teaching then, though there will be other things to do before the examinations start in January.

I’ve managed to keep a reasonable pace up in both sets of lectures. The last one due this term is for Vector Calculus and Fourier Series, on Friday 18th December, but I think I may be able to complete the module content on the Tuesday lecture which means the students will be able to have a bit more time to relax before Christmas or, alternatively, a bit more time for revision. I hope it’s the former, as I imagine the students are at least as tired as we staff are. This has been a difficult year for everyone.

At Maynooth University, lectures for Semester 2 start on February 1st 2020. That will give us a bit of time to see how the Covid-19 pandemic progresses before deciding exactly how we’re going to approach teaching. Other universities that resume earlier have less time to make this decisions. I fear that the number of cases may rise rapidly over the three weeks remaining before Christmas, even before the Christmas break itself, and we therefore might have to go fully online next term. What I don’t want to happen is what happened in September, namely that we made elaborate plans for lecture rotations and tutorial groups that were then ditched because the Coronavirus situation changed. That was quite demoralizing because it involved a great deal of effort that was wasted.

Being a Department of Theoretical Physics we don’t have the problems facing the more experimental subjects that require extensive laboratory classes which are difficult to do under social distancing. Next term however we do have Computational Physics, which has laboratory classes, so I’ll have to decide how much of that we can do in person and how much students will have to do online using their laptops. I hope we can return to full in-person lab sessions, but we can’t be that will be possible right now. In any case computer labs are far easier to run online that practical chemistry or physics labs, so I think we will be able to do a reasonable job whatever the circumstances.

For added fun, next term I’ll be teaching a new module; 4th Year Advanced Electromagnetism. Although there’s always a lot of work required to teach a module for the first time, I am actually looking forward to doing this one as there’s some interesting physics in it (especially relativistic electrodynamics). I may try to squeeze a bit of plasma physics in too. But will it be online or on campus, or a mixture of both? Time alone will tell.

Anyway I’m looking forward to this weekend being as stress-free as possible. There’s a good start tonight, as Newcastle’s game against Aston Villa has been postponed due to Covid-19 so no anxious looking at the score this evening. The rest of the weekend will be dominated, for me, by the two semi-finals of the All Ireland Gaelic Football Championship (Cavan versus Dublin tomorrow and Mayo versus Tipperary on Sunday). It seems to be written in the stars that the final should be Dublin versus Tipperary, the two teams that played on Bloody Sunday, but time will tell on that one too.

Update: Dublin did indeed comfortably beat Cavan on Saturday but Mayo beat Tipperary in a high scoring game in a foggy Croke Park on Sunday (Mayo 5-20 Tipperary 3-13). The final will therefore not be a rerun of the 1920 final.

That’s enough rambling. Have a good weekend.