Keywords: Real 2-space as square grid.png „ <sup>2</sup> The image is made in raster graphics deliberately such that its pixel structure matches the „ <sup>2</sup> structure exactly a unit interval equals to 20px along both axes It may not be rescaled own Incnis Mrsi <font color 000099> ”¼</font> coordinate axes x 0 ˆ¨ y 0 <font color 00CCCC> ”‚</font> integer x except 0 <font color 009900> ” </font> integer y except 0 <font color FF9900> ”¼</font> x ˆ’ 1 2 ˆˆ Z ˆ¨ y ˆ’ 1 2 ˆˆ Z except cases above <font color FF00FF> – </font> 10x ˆˆ Z ˆ§ 10y ˆˆ Z except cases above <font color FF99FF> ” ”‚</font> 10x ˆˆ Z ˆ¨ 10y ˆˆ Z except cases above Cartesian coordinates plane Grids coordinate systems Real numbers Cc-zero |