Let Fq be a finite field with and n>0 an integer with gcd(n,logpq)=1. Let be the Fq-monomorphism defined by for 0≤i<n−1 and . For 05f4d4bf8ad73d2a9fa07e38d9b1aa60" title="Click to view the MathML source">f,g∈Fq(x0,…,xn−1)∖Fq, define f∘g=f(g,g⁎,…,g(n−1)⁎). Then is a monoid whose invertible elements are called global P-forms. Global P-forms were first introduced by H. Dobbertin in 2001 with q=2 to study a certain type of permutation polynomials of F2m with 0594106a757be70d5c75339baddbc5d4" title="Click to view the MathML source">gcd(m,n)=1; global P-forms with 0575" title="Click to view the MathML source">q=p for an arbitrary prime p were considered by W. More in 2005. In this paper, we discuss some fundamental questions about global P-forms, some of which are answered and others remain open.