Add some notes about the basic mathematical laws that the system presumes hold true for operators in a btree operator family.  This is mostly to clarify my own thinking about what the planner can assume for optimization purposes.  (blowing dust off an old abstract-algebra textbook...)
Add some notes about the basic mathematical laws that the system presumes
hold true for operators in a btree operator family.  This is mostly to
clarify my own thinking about what the planner can assume for optimization
purposes.  (blowing dust off an old abstract-algebra textbook...)

lintzc/gpdb,lpetrov-pivotal/gpdb,edespino/gpdb,Quikling/gpdb,zeroae/postgres-xl,xuegang/gpdb,atris/gpdb,Chibin/gpdb,kmjungersen/PostgresXL,atris/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,zeroae/postgres-xl,cjcjameson/gpdb,royc1/gpdb,chrishajas/gpdb,xinzweb/gpdb,royc1/gpdb,yuanzhao/gpdb,0x0FFF/gpdb,lintzc/gpdb,jmcatamney/gpdb,arcivanov/postgres-xl,0x0FFF/gpdb,yazun/postgres-xl,postmind-net/postgres-xl,lintzc/gpdb,edespino/gpdb,lintzc/gpdb,royc1/gpdb,snaga/postgres-xl,oberstet/postgres-xl,xuegang/gpdb,foyzur/gpdb,snaga/postgres-xl,rvs/gpdb,Quikling/gpdb,ahachete/gpdb,oberstet/postgres-xl,rvs/gpdb,tangp3/gpdb,Quikling/gpdb,arcivanov/postgres-xl,Chibin/gpdb,edespino/gpdb,arcivanov/postgres-xl,rubikloud/gpdb,xuegang/gpdb,CraigHarris/gpdb,lisakowen/gpdb,chrishajas/gpdb,zeroae/postgres-xl,ashwinstar/gpdb,tangp3/gpdb,chrishajas/gpdb,chrishajas/gpdb,janebeckman/gpdb,Postgres-XL/Postgres-XL,tangp3/gpdb,lintzc/gpdb,foyzur/gpdb,techdragon/Postgres-XL,greenplum-db/gpdb,Quikling/gpdb,Chibin/gpdb,tangp3/gpdb,jmcatamney/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,foyzur/gpdb,greenplum-db/gpdb,atris/gpdb,lintzc/gpdb,kaknikhil/gpdb,randomtask1155/gpdb,xinzweb/gpdb,oberstet/postgres-xl,techdragon/Postgres-XL,ahachete/gpdb,edespino/gpdb,zeroae/postgres-xl,arcivanov/postgres-xl,pavanvd/postgres-xl,yuanzhao/gpdb,xinzweb/gpdb,lpetrov-pivotal/gpdb,0x0FFF/gpdb,kaknikhil/gpdb,Chibin/gpdb,rvs/gpdb,cjcjameson/gpdb,royc1/gpdb,adam8157/gpdb,lintzc/gpdb,greenplum-db/gpdb,foyzur/gpdb,rubikloud/gpdb,yazun/postgres-xl,foyzur/gpdb,lpetrov-pivotal/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,ovr/postgres-xl,cjcjameson/gpdb,randomtask1155/gpdb,lpetrov-pivotal/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lisakowen/gpdb,0x0FFF/gpdb,pavanvd/postgres-xl,tpostgres-projects/tPostgres,rvs/gpdb,Quikling/gpdb,ovr/postgres-xl,janebeckman/gpdb,xinzweb/gpdb,Chibin/gpdb,ahachete/gpdb,yazun/postgres-xl,kaknikhil/gpdb,janebeckman/gpdb,50wu/gpdb,lpetrov-pivotal/gpdb,jmcatamney/gpdb,Postgres-XL/Postgres-XL,cjcjameson/gpdb,randomtask1155/gpdb,foyzur/gpdb,xuegang/gpdb,yuanzhao/gpdb,edespino/gpdb,randomtask1155/gpdb,xinzweb/gpdb,postmind-net/postgres-xl,rubikloud/gpdb,Chibin/gpdb,janebeckman/gpdb,atris/gpdb,rubikloud/gpdb,jmcatamney/gpdb,atris/gpdb,lisakowen/gpdb,lpetrov-pivotal/gpdb,lisakowen/gpdb,greenplum-db/gpdb,chrishajas/gpdb,ovr/postgres-xl,xuegang/gpdb,tangp3/gpdb,Quikling/gpdb,50wu/gpdb,lintzc/gpdb,postmind-net/postgres-xl,cjcjameson/gpdb,tangp3/gpdb,randomtask1155/gpdb,cjcjameson/gpdb,lisakowen/gpdb,tangp3/gpdb,zaksoup/gpdb,yazun/postgres-xl,kaknikhil/gpdb,Postgres-XL/Postgres-XL,janebeckman/gpdb,atris/gpdb,ahachete/gpdb,rvs/gpdb,xuegang/gpdb,rvs/gpdb,janebeckman/gpdb,royc1/gpdb,kmjungersen/PostgresXL,xuegang/gpdb,yuanzhao/gpdb,ahachete/gpdb,yuanzhao/gpdb,lintzc/gpdb,ahachete/gpdb,CraigHarris/gpdb,chrishajas/gpdb,royc1/gpdb,edespino/gpdb,ashwinstar/gpdb,zaksoup/gpdb,adam8157/gpdb,randomtask1155/gpdb,techdragon/Postgres-XL,lisakowen/gpdb,zaksoup/gpdb,cjcjameson/gpdb,oberstet/postgres-xl,arcivanov/postgres-xl,50wu/gpdb,lisakowen/gpdb,Quikling/gpdb,xinzweb/gpdb,yuanzhao/gpdb,tpostgres-projects/tPostgres,lpetrov-pivotal/gpdb,0x0FFF/gpdb,zaksoup/gpdb,xinzweb/gpdb,cjcjameson/gpdb,yuanzhao/gpdb,rubikloud/gpdb,rvs/gpdb,chrishajas/gpdb,rubikloud/gpdb,rvs/gpdb,oberstet/postgres-xl,zaksoup/gpdb,kmjungersen/PostgresXL,edespino/gpdb,Chibin/gpdb,atris/gpdb,Quikling/gpdb,greenplum-db/gpdb,50wu/gpdb,yuanzhao/gpdb,janebeckman/gpdb,pavanvd/postgres-xl,royc1/gpdb,edespino/gpdb,kaknikhil/gpdb,zaksoup/gpdb,kaknikhil/gpdb,Chibin/gpdb,janebeckman/gpdb,adam8157/gpdb,zeroae/postgres-xl,snaga/postgres-xl,50wu/gpdb,edespino/gpdb,adam8157/gpdb,Quikling/gpdb,xuegang/gpdb,ashwinstar/gpdb,ovr/postgres-xl,zaksoup/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,kmjungersen/PostgresXL,techdragon/Postgres-XL,50wu/gpdb,rvs/gpdb,adam8157/gpdb,CraigHarris/gpdb,ashwinstar/gpdb,postmind-net/postgres-xl,ashwinstar/gpdb,janebeckman/gpdb,ahachete/gpdb,ahachete/gpdb,greenplum-db/gpdb,adam8157/gpdb,adam8157/gpdb,CraigHarris/gpdb,0x0FFF/gpdb,xinzweb/gpdb,edespino/gpdb,0x0FFF/gpdb,janebeckman/gpdb,rubikloud/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,pavanvd/postgres-xl,CraigHarris/gpdb,foyzur/gpdb,zaksoup/gpdb,jmcatamney/gpdb,postmind-net/postgres-xl,foyzur/gpdb,jmcatamney/gpdb,lpetrov-pivotal/gpdb,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,yuanzhao/gpdb,rubikloud/gpdb,randomtask1155/gpdb,snaga/postgres-xl,ovr/postgres-xl,randomtask1155/gpdb,0x0FFF/gpdb,CraigHarris/gpdb,greenplum-db/gpdb,Quikling/gpdb,Chibin/gpdb,ashwinstar/gpdb,yazun/postgres-xl,tpostgres-projects/tPostgres,CraigHarris/gpdb,greenplum-db/gpdb,royc1/gpdb,chrishajas/gpdb,rvs/gpdb,arcivanov/postgres-xl,tangp3/gpdb,xuegang/gpdb,adam8157/gpdb,tpostgres-projects/tPostgres,50wu/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,atris/gpdb,Chibin/gpdb,techdragon/Postgres-XL,50wu/gpdb