ABSTRACT
In 1971, K.G.Wilson published the first renormalization group treatment of critical phenomena and was honoured a decade later by the Nobel prize for physics (though in the cumulative author index of the journal at that time the articles were forgotten). It is an attempt to justify the scaling assumptions made earlier, and to calculate the critical exponents entering these scaling assumptions. Historically, it was first applied to thermal phase transitions and only afterwards to percolation; also initially it dealt with fluctuations in Fourier space (as function of wave vector) and only later moved to real space (where everything depends on distances). Ignoring this history, we will concentrate on real-space renormalization of percolation (sometimes also called position space renormalization). This seems the simplest way to introduce renormalization ideas into percolation theory (Reynolds et al., 1980) since the method becomes for large lattices equivalent to finite-size scaling. Thus we will first explain finite-size scaling and then go to renormalization techniques.
