## Section: New Results

### The Negligible and Yet Subtle Cost of Pattern Matching

Participant : Beniamino Accattoli.

This joint work with Bruno Barras (Inria) [31] belongs to line of work *Cost Models and Abstract Machines for Functional Languages*, supported by the ANR project COCA HOLA.

In this work we extend results about time cost models for the $\lambda $-calculus to a larger language, namely the $\lambda $-calculus with constructors and pattern matching. We consider all natural evaluation strategies, that is, call-by-name, call-by-value, and call-by-need.

The results are expected, and considered folklore, but we show that the question is subtler than it seems at first sight, by exhibiting some counter-example for naive formulations of the extensions. The, we show the actual results for the right extensions.