Solution problem 23 of the Early Examination in Informatics 2018 via the mapping method (08.2016)

One more <<proof>> of Helen Mironchick's axiom - there is no such system of equations in Boolean variables that could not be solved via the mapping method

   Actually we have the system

    (x1⊕x2)^(x1=>y1) =1
    (x2⊕x3)^(x2=>y2) =1
    (x3⊕x4)^(x3=>y3) =1
     . . . . . . . . . . . . . .
    (x6⊕x7)^(x6=>y6) =1 
    x7=>y7 =1 

     Solution via technique 08/2016 (Helen Mironchick)

   References
   1.  http://kpolyakov.spb.ru/download/mea-2016-8.pdf