$MinPrecision
 Usage
• $MinPrecision gives the minimum number of digits of precision to be allowed in arbitrary-precision numbers.
Notes
• The default value of $MinPrecision is -Infinity. • Positive values of $MinPrecision make Mathematica pad arbitrary-precision numbers with zero digits to achieve the specified nominal precision. The zero digits are taken to be in base 2, and may not correspond to zeros in base 10. • $MaxPrecision = $MinPrecision = n makes Mathematica do fixed-precision arithmetic. • $MinPrecision is measured in decimal digits, and need not be an integer. • New in Version 3; modified in 5.
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