Key legal question
Whether the original perimeter decision was void rather than merely challengeable.
Extracted holding
The defects alleged by the appellant were not of the kind that would render the decision void; the act was at most challengeable in ordinary proceedings.
Extracted reasoning
Nullity requires a particularly serious defect that is obvious or easily recognizable and does not seriously endanger legal certainty; the complaints about unequal burden, cost coverage, equivalence, and classification of special assessments did not meet that threshold.