# Recent News

# 2022

Polarization I pretty much nailed all my predictions for 2021, in particular I wrote about right-wing extremism:
I fully expect Trump, unconstrained by the people that surround him in the White House today, to become even more unhinged and try to inspire even more violent acts of terrorism."
I wrote that two weeks before Jan 6th.
I also wrote about the roots of that violence as a loss of power:

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# Perfetto SPAN_JOIN and LEAD Explained

Perfetto and the SQL processing built into trace_processor are both fantastic, but two of the most important parts of that SQL processing are not well documented, at least for my simple brain.
The first feature is SPAN_JOIN which is described as:
Span join is a custom operator table which computes the intersection of spans of time from two tables or views.
There is a nice diagram showing how the spans are combined:

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# Random Integer Matrices With Inverses That Are Also Integer Matrices

I want to generate a random integer valued \( n \times n \) matrix \( A \) whose inverse is also an integer valued matrix, i.e. how can I generate Unimodular matrices?
The key is starting with an \( n \times n \) identity matrix \( I \), which has a determinant of 1. Then you can apply row operations to \( I \) that keep the determinant 1, i.e. by picking row operations that are expressible as multiplication by a matrix that also has a determinant of 1 with integer components.

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# The Seeds of Delusion

Remember that nauseous feeling you had on waking up on Nov 5, 2016 to a Trump presidency? For me, the root of that nausea was the dawning realization that a majority of my fellow Americans were deeply racist, or at least there was enough of them to propel Trump to the highest office in the land.
I’m not naive, I always knew there were racist people, but I presumed they weren’t a majority, they were a minority, and a shrinking minority at that.

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# Get Vaccinated

From the Cleveland Clinic, Most COVID-19 Infections and Hospitalizations are in Unvaccinated.
“From January first to around mid-April, we’ve had around 4,300 admissions to the hospital with COVID. Of those patients, 99% were not fully vaccinated,” said Eduardo Mireles, MD, Director of the Medical Intensive Care Unit.
So in case it isn’t obvious, please get vaccinated.
Also, we all know the majority of people not getting vaccinated are the followers of Winnie The Coup, which will only fuel more conspiracy theories in future years when, for some unknown reason, the percentage of R deaths, hospitalizations, and instances of long Covid will be found to swamp the rest of the US population.

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