Basic functionality of math functions floor and ceiling works properly as [1] describes, but these functions doesn't accept number as parameter.

Reference service which supports OData V4:
ULR: http://services.odata.org/V4/Northwind/Northwind.svc/Employees/?$filter=EmployeeID%20eq%20floor(4.2)
Result: Employee with ID 4

ULR: http://localhost:8080/odata4/olingo_basic/Source/SimpleTableView/?$filter=intkey%20eq%20floor(4.2)
Actual result: {"error":{"code": null, "message": "TEIID30069 The function 'FLOOR(?)' has more than one possible signature."}}
Expected result: Entity with intkey 4

ULR:  http://localhost:8080/odata4/olingo_basic/Source/SimpleTableView/?$filter=intkey%20eq%20ceiling(4.2)
Actual result: {"error": {"code": null, "message": "TEIID30069 The function 'CEILING(?)' has more than one possible signature."}}
Expected result: Entity with intkey 5

See [OData-ABNF] http://docs.oasis-open.org/odata/odata/v4.0/errata02/os/complete/abnf/odata-abnf-construction-rules.txt Line: 539 - Math functions accepts commonExpr

[1] http://docs.oasis-open.org/odata/odata/v4.0/errata02/os/complete/part2-url-conventions/odata-v4.0-errata02-os-part2-url-conventions-complete.html#_Toc406398142