The fixed-point function g(x, y) obeys symmetry: g(-x, y)=g(x, y), 
hence, the RG equation g(x, y)=a^2*g(a^(-1)g(-x/a,-y*w),y*w^2+w)
(differs with a minus sign at x/a in the argument of the function 
in the right-hand part) is equivalent to the original. 

The solution is approximated by a polynomial in a strip |x-0.9*y|<0.1, 
as a serios ower powers of X=10*(x-0.9*y) and y.  

g(x,y)=1-1.02130447*y   
-0.37911340*y^2 -0.05209698*y^3 +0.67473928*y^4 +0.07227462*y^5 
-0.43957387*y^6 -0.03480062*y^7 +0.26446563*y^8 +0.02947221*y^9 
-0.16098478*y^10-0.02190669*y^11+0.09580085*y^12+0.01350816*y^13
-0.05308730*y^14-0.00645537*y^15+0.02538446*y^16+0.00202832*y^17
-0.00934447*y^18-0.00030319*y^19+0.00225054*y^20-0.00025780*y^22

+X*(0.34235298*y+0.06353800*y^2 -0.44509778*y^3 -0.03979205*y^4
+0.39253772*y^5 +0.03884192*y^6 -0.31363838*y^7 -0.04047731*y^8
+0.23560707*y^9 +0.03579302*y^10-0.16488094*y^11-0.02740810*y^12
+0.10364139*y^13+0.01710208*y^14-0.05420538*y^15-0.00783799*y^16
+0.02107217*y^17+0.00227080*y^18-0.00518480*y^19-0.00030543*y^20
+0.00058631*y^21)

+X^2*(0.01901960+0.00352986*y   +0.04402881*y^2 +0.00511104*y^3
-0.09743262*y^4 -0.01223784*y^5 +0.12353806*y^6 +0.01782001*y^7
-0.12621169*y^8 -0.02066626*y^9 +0.11315701*y^10+0.01957669*y^11
-0.09030592*y^12-0.01451488*y^13+0.06227572*y^14+0.00772443*y^15
-0.03490403*y^16-0.00256446*y^17+0.01456024*y^18+0.00039249*y^19
-0.00394702*y^20+0.00051560*y^22)

+X^3*(0.00763963*y+0.00081372*y^2-0.00093900*y^3+0.00003480*y^4
-0.01258157*y^5 -0.00213476*y^6 +0.02549268*y^7 +0.00459465*y^8
-0.03312989*y^9 -0.00616124*y^10+0.03303204*y^11+0.00577998*y^12
-0.02526217*y^13-0.00366196*y^14+0.01380684*y^15+0.00139708*y^16
-0.00471447*y^17-0.00024072*y^18+0.00074425*y^19)

+X^4*(0.00021221+0.00002274*y   +0.00168396*y^2 +0.00022696*y^3
-0.00214055*y^4 -0.00030864*y^5 +0.00032856*y^6 +0.00001255*y^7
+0.00277821*y^8 +0.00050945*y^9 -0.00536034*y^10-0.00083861*y^11
+0.00574661*y^12+0.00070631*y^13-0.00387392*y^14-0.00032214*y^15
+0.00152596*y^16+0.00006275*y^17-0.00026779*y^18)

+X^5*(0.00000001+0.00011406*y   +0.00001483*y^2 +0.00021300*y^3
+0.00003970*y^4 -0.00062157*y^5 -0.00011539*y^6 +0.00072531*y^7
+0.00012907*y^8 -0.00049621*y^9 -0.00007304*y^10+0.00019441*y^11
+0.00001720*y^12-0.00003361*y^13)

+X^6*(0.00000212+0.00000012*y   +0.00003455*y^2 +0.00000730*y^3
-0.00000632*y^4 -0.00000791*y^5 -0.00007855*y^6 +0.00000260*y^7
+0.00012214*y^8 -0.00008043*y^10+0.00002074*y^12)

+X^7*(-0.00000001+0.00000137*y  +0.00000050*y^2 +0.00000778*y^3
+0.00000020*y^4 -0.00001423*y^5 -0.00000033*y^6 +0.00000969*y^7
-0.00000251*y^9)

+X^8*(0.00000002+0.00000006*y   +0.00000079*y^2 -0.00000048*y^4)

+X^9* 0.00000005*y