Singular Manual: crystallographicGroupP1

| #### 7.10.2.7 crystallographicGroupP1 Procedure from library `fpalgebras.lib` (see fpalgebras_lib). Usage: crystallographicGroupP1(d); d an integer Return: ring Note: - the ring contains the ideal I, which contains the required relations - p1 group with the following presentation < x, y | [x, y] = 1 > -d gives the degreebound for the Letterplace ring Example:
    LIB "fpalgebras.lib";
    def R = crystallographicGroupP1(5); setring R;
    I;
    ==> I[1]=y*x+x*y+1
    ==> I[2]=X*x+1
    ==> I[3]=x*X+1
    ==> I[4]=y*Y+1
    ==> I[5]=Y*y+1

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