let F be non empty Graph-yielding Function; :: thesis: for x, z being Element of dom F
for x9 being Element of dom (canGFDistinction (F,z)) st x = x9 holds
(canGFDistinction (F,z)) . x9 is F . x -Disomorphic

let x, z be Element of dom F; :: thesis: for x9 being Element of dom (canGFDistinction (F,z)) st x = x9 holds
(canGFDistinction (F,z)) . x9 is F . x -Disomorphic

let x9 be Element of dom (canGFDistinction (F,z)); :: thesis: ( x = x9 implies (canGFDistinction (F,z)) . x9 is F . x -Disomorphic )
assume A1: x = x9 ; :: thesis: (canGFDistinction (F,z)) . x9 is F . x -Disomorphic
per cases ( x = z or x <> z ) ;
end;