Since DMNv1.2 the spec dropped the equivalence of:

[a] = a

because it does not apply to the statement that

a singleton list L, when used in an expression where a list is not expected, behaves as if L[1] is written.

So the expression

[a] = a

on DMNv1.2 is expected to return false.

However, in section 10.3.2.6 Context of the spec, it provides the following statement for the get entries function:

To retrieve a list of key,value pairs from a context m, the following built-in function may be used: get entries(m).
For example, the following is true:

get entries({key 1 : "value 1 "})[key="key 1 "].value = "value 1 "

BUT

get entries({key1 : "value1"})[key="key1"].value = "value1"

  by substitution:

[ { key : "key1", value : "value1" } ][key="key1"].value = "value1"
[ { key : "key1", value : "value1" } ].value = "value1"
[ "value1" ] = "value1"

according to DMNv1.2 should be false

By the same principle that the DMNv1.2 for the following literal expression:

[123] = 123

on DMNv1.2 is expected to be false

some built in functions are overloaded in that they can have multiple signatures. So, say, performing an "instance of" to compare against the function "min" is meaningless as the signature is not known unless it is invoked.

Unless the type system is to take into account overloaded functions?

Situational Data is the set of Data Items and their structures that are needed for the performance and understanding of a Knowledge Package Model.
The details of the Data Items will usually be a subset of the “official” complexity of those items in the environment of the Knowledge Package Model.
For example, the official definition of the Data Item for Blood Pressure (in healthcare) includes more than 50 properties. A Data Item in a Situational Data Model may need only 2 of those properties for execution of the Processes, Cases, and or Decision Services.
Semantic References can be added to link the Data Item to the “official” details.
Uses of the Data Items in BPM+ models that determine the scope of Situational Data include:
Data required for DMN Decisions
Data required for BPMN Gateways transitions
Data required to be passed to/from services invoked by BPMN and CMMN
Data required to trigger Sentries in CMMN
Etc.

The spec sometimes refers to the temporal precision as milliseconds and sometimes to seconds. Sections 10.3.2.3.3, 10.3.2.3.5 and 10.3.2.3.6 refer to Seconds whereas table 48 offers a semantic of Milliseconds

the builtin function is() refers to this section. It should cover some pos/neg examples of equality vs. identity, and explain aggregate elements in D, e.g. list of structures.

E.g. in aggregation, default for item definition, see examples in DMN-2, where filters like [item!=null] are used repeatedly