## Mathematicians Of The Day

### 25th October

On this day in 1713, Gottfried Leibniz, in a letter to Johann Bernoulli, observed that an alternating series whose terms monotonically decrease to zero in absolute value is convergent.

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##### Born:

- 1811: Évariste Galois Ⓟ
- 1886: Lester R Ford Ⓟ
- 1926: James Eells Ⓟ

##### Died:

- 1647: Evangelista Torricelli Ⓟ
- 1733: Giovanni Saccheri
- 1884: Alberto Castigliano Ⓟ
- 1905: Otto Stolz Ⓟ
- 1914: Wilhelm Lexis Ⓟ
- 1933: Albert Wangerin Ⓟ
- 1970: Edward Collingwood Ⓟ
- 1996: Ennio De Giorgi Ⓟ
- 1997: Mina Rees Ⓟ
- 2002: René Thom Ⓟ

#### Quotation of the day

##### From René Thom

If one must choose between rigour and meaning, I shall unhesitatingly choose the latter.