// environment
definition nonpayable(env e) returns bool = e.msg.value == 0;
definition nonzerosender(env e) returns bool = e.msg.sender != 0;

// constants
definition max_uint48() returns mathint = (1 << 48) - 1;

// math
definition min(mathint a, mathint b) returns mathint = a < b ? a : b;
definition max(mathint a, mathint b) returns mathint = a > b ? a : b;