There is duality between monitors and message passing. What is that duality exactly? In the table, the rows represent notions about monitors, and the columns represent notions about message passing. Match the columns in a cell to represent that a notion about monitors is dual to a notion about message passing. `request` channel and operation kinds arms of case statement on operation kind retrieve and process pending request `send request(); receive reply()` save pending request local server variables `send reply()` `receive request()` procedure bodies monitor entry permanent variables `wait` procedure identifiers `signal` procedure call procedure return arms of `request` retrieve case `send channel and save local statement request(); `send `receive and process pending server on receive reply()` request()` operation pending request variables operation reply()` kinds request kind procedure bodies monitor entry permanent variables `wait` procedure identifiers `signal` procedure call procedure return.

1. There is duality between monitors and message passing. What is that duality exactly?
In the table, the rows represent notions about monitors, and the columns represent notions about
message passing.
Match the columns in a cell to represent that a notion about monitors is dual to a notion about
message passing.
`request` channel and operation kinds
arms of case statement on operation kind
retrieve and process pending request
`send request(); receive reply()`
save pending request
local server variables
`send reply()`
`receive request()`
procedure bodies
monitor entry
permanent variables
`wait`
procedure identifiers
`signal`
procedure call
procedure return
`request`
channel
and
operation
kinds
arms of
case
statement
on
operation
kind
retrieve
and
process
pending
request
`send
request();
receive
reply()`
save
pending
request
local
server
variables
`send
reply()`
`receive
request()`

2. procedure
bodies
monitor
entry
permanent
variables
`wait`
procedure
identifiers
`signal`
procedure
call
procedure
return