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pdf format - Little triangles appearing in a Mathematica region plot with "opacity" saved in a PDF file



I am trying to produce a region plot of many functions, but Mathematica keeps showing me the little triangles when I save it as pdf. I have seen other solutions which fix the problem with PlotStyle-> color, but the problem here is the opacity of each plot.


An example:


RegionPlot[{Cos[x^2 y] > 0, Sinc[x y + x y^2] <= 0.3}, {x, -1, 1}, {y, -1, 10}]


will produce this plot:


I had to take a screen shot of the pdf, because I could not upload the pdf here


I saw on the internet suggestions such as:


g2 = p2 /. {Polygon[__] -> {}}

Or some functions that include


PlotPoints -> 100

But that does not work when you have two functions superposed over each other. Of course, you might suggest that I use Show then two region plots, but I don't want to deal with the opacity of each plot, and would rather have Mathematica do that for me.


Any suggestions?





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