Celebratio Mathematica

Thomas Milton Liggett

Memory for Tom

by Wenpin Tang

I first met Tom in March, 2017, when I de­cided to ac­cept a postdoc of­fer from UCLA. One reas­on for mak­ing such a de­cision was Tom him­self — I es­pe­cially ap­pre­ci­ated his “less­er” known res­ults in trans­port­ing ran­dom meas­ures and one-de­pend­ent pro­cesses (with An­der Hol­royd). He was more ap­proach­able than I ex­pec­ted, and we talked a lot about the Cali­for­nia life dur­ing our first lunch meet­ing.

We began dis­cuss­ing re­search in Septem­ber of 2017 when I ar­rived at UCLA. This was 6 years after Tom’s re­tire­ment from the UCLA math de­part­ment, but Tom was still very act­ive in re­search. The top­ic that Tom shared with me was one-de­pend­ent pro­cesses on gen­er­al graphs, which he had de­veloped an in­terest in dur­ing the last few years. We then col­lab­or­ated on this pro­ject for the next 18 months un­til Tom star­ted hav­ing ser­i­ous health prob­lems. What was sur­pris­ing to me was Tom’s in­tense in­volve­ment in the pro­ject. We had weekly meet­ings, and he reg­u­larly wrote me some “ready-to-go” Latex notes, which I be­lieve to be un­com­mon for dis­tin­guished re­search­ers of Tom’s stature. His re­cipe of do­ing re­search was simple: start with the small cases and then gen­er­al­ize. Ma­gic­ally, he ap­peared to be al­ways suc­cess­ful (al­though he told me he did fail a few times). I feel quite for­tu­nate to be one of his last col­lab­or­at­ors.

Be­sides re­search, Tom was also will­ing to share his life. I re­mem­ber each vis­it to his house, chat­ting about the “re­search-type” life for hours, and I al­ways found Tom to be a good story tell­er. I also re­mem­ber the swim­ming pool party Tom or­gan­ized every year, and lik­ing a lot the smoked tur­key that he and his wife Chris pre­pared for us. Tom was a fas­cin­at­ing edu­cat­or, a great col­lab­or­at­or, and an ad­or­able per­son. I miss him a lot.

Wen­pin Tang is an As­sist­ant Pro­fess­or at the De­part­ment of In­dus­tri­al En­gin­eer­ing and Op­er­a­tions Re­search at Columbia Uni­versity in New York City.