## VUI Ha Huy, DUC Nguyen Hong,

## A formula for the \L ojasiewicz exponent at infinity in the real plane via real approximations.

## Hokkaido Mathematical Journal, 38 (2009) pp.417-425

### Fulltext

PDF### Abstract

We compute the \L ojasiewicz exponent of $f=(f_1,\ldots,f_n)\colon \Bbb R^2\to\Bbb R^n$ via the real approximation of Puiseux's expansions at infinity of the curve $f_1\ldots f_n=0$. As a consequence we construct a collection of real meromorphic curves which provide a testing set for properness of $f$ as well as a condition, which is very easy to check, for a local diffeomorphism to be a global one.

MSC(Primary) | 14R25 |
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MSC(Secondary) | 32A20, 32S05 |

Uncontrolled Keywords | \L ojasiewicz exponent at infinity, Puiseux expansion at infinity, Testing sets for properness of polynomial mappings. |