# Sylvie Paycha

The portrait of a formula uses a dictionary which provides a graphic representation of the mathematical ingredients of the formula. Without aiming at a faithful translation which would enable a full reconstruction of the initial formula from the portrait, this pictorial translation reveals the syntax of the formula to a non mathematician. The translation should be faithful enough so as to distinguish a correct transcription from an incorrect one. Setting up a dictionary is where art comes into play, whereas the constraints lie in the realization of the portrait of the formula following the rules set by the dictionary.

This is a pictorial transcription of a formula d_t u= f( t,x, u, d_xu) which arises in one form of the so-called Cauchy-Kovalevskaia theorem. This portrait of the formula uses a dictionary as explained above. The derivatives are represented here by deviating arrows, the variables by geometric figures of different colours, the function by an oscillating curve (symbolizing its graph) and the equality by the arrow of a balance scale.