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Teo tells us about his work in artificial intelligence, his travels around the world, and how inspiration sometimes strikes in the pub.

Clouds make the weather, yet their detail isn't taken into account in weather forecasts. Artificial intelligence might be able to help.

Predicting the weather is hard. With more data and computing power becoming available, artificial intelligence can help.

How does your phone know what the weather's going to be like?

How a little insect can cause chaos.

Extreme care is needed when dealing with infinite sums. From what I can tell, it seems that confusion arises when people assume they are allowed to manipulate infinite sums in the same way as they are used to doing with the finite sums they are accustomed to dealing with. Assuming infinite sums behave anything like finite sums will lead to problems. Reordering a non-convergent infinite sum will often produce different answers - in many cases you can get any result you desire, but it's clearly incorrect. Proceeding term-by-term to calculate the partial sums. What does it even mean to sum an infinite number of terms when the sum is non-convergent? It's unsafe to assume that what works for finite sums must apply to infinite sums as well.

Regarding -1 + -1 ... (Grandi's Series), although it doesn't have a limit, it is Cesaro summable and as a cesaro sum of 1/2. This can be easily proved in lots of ways. This is what Numberphile were talking about no doubt.