"extant rules" is correct and usable in written English.
It is commonly used to refer to rules that are still in effect. For example, "The couple was aware of the extant rules regarding their property prior to their divorce."
Uber grew by ignoring extant transport rules.
The TUEs have raised questions because of their proximity to major race dates on the 2012 Tour winner's schedule and the head of the UCI, Brian Cookson, has said he felt in this instance Team Sky may have gone close to the limit of the rules extant at the time while staying within the bounds of what was permitted.
The legal responsibilities of businesses imply that these entities must fulfil their economic mission within the extant framework of rules and regulatory parameters.
However, inventory data available to these community forests are inadequate for carbon estimation as they were done for timber exploitation as required by extant community forestry rules.
Although extant data limitations ruled out constructing a stratified model, two considerations give studying demographic heterogeneity priority for future work.
Extant algorithms to mine rules with minimum single constraints might encounter problem, named (({P}_{2})), such as the generation of many redundant candidate rules and the duplicates of solutions that are then eliminated.
NND increases in approximate isometry with stem diameter, indicating conformation to the same spatial packing rules found in extant forests and other fossil forests of varying ages.
Single-loop learning occurs when people search for another strategy to address the error and work with, or within, the governing variables, so that extant goals, values, plans and rule are operationalized rather than questioned.
[While WGDs do not seem readily traceable in extant prokaryote genomes, they cannot be ruled out either over long evolutionary time scales (e.g. > 500 MY).
The absence of extant Bauhinia in Europe does not immediately rule out the NALB as a possible migration pathway.
