Mathematicians Solve Longstanding Four-Strand Braid Question

Joan Birman was a mathematician who wanted to keep doing maths after she retired.

In 2019, a 15-year-old student named Vasudha Bharathram contacted her for help.

Birman introduced her to braids, which are strands that cross over and under one another.

The two began studying a difficult question about how braids can be represented using algebra.

Later, mathematician Tara Brendle joined them.

The question concerned braids with four strands, a case that had remained unresolved.

Instead of checking many examples one by one, the team found a way to use a method involving five-strand braids.

They posted a paper about their work in July.