Fixed-point substitution is scanned across candidate values. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A fixed point is found by substitution

The checked source row is the middle row: one half returns one half.

f(x)=x2+14f(x)=\frac{x}{2}+\frac{1}{4}
Fixed candidate sourceThe source diagram validates the fixed-bit row.mapId=affine_contractionparameter=nonecandidate=1/2outputValue=1/2fixedBit=1 bit

Neighbor candidates fail the same substitution

The table keeps the map fixed and changes only the candidate. The fixed bit turns on only when output and candidate match.

xf(x)fixed bit0140121211340\begin{array}{c|c|c}x&f(x)&\text{fixed bit}\\0&\frac{1}{4}&0\\\frac{1}{2}&\frac{1}{2}&1\\1&\frac{3}{4}&0\\\end{array}
Fixed candidate scanThe accepted row shares the checked source.mapId=affine_contractionparameter=nonecandidate=1/2outputValue=1/2fixedBit=1 bit